and its continual lack of any profitable return was a sore spot to legislators. As he studied and advanced, Nelson found he could understand why the old stuck-in-the-mud Greenface thinkers thought that way. It was true that since people had learned how to make any element or raw material out of synthetic atoms back in the last century, the twenty-first, Martian mining had come to a halt. Now all that the Mars colonists could hope to contribute was knowledge. And they had failed to do so. In fact, their efforts were pretty well stumped.

But the old debate about the Martian costs had cropped up again the very week that Nelson had graduated and shipped back home aboard the passenger liner Congreve. He had been busy packing, saying good-by to his friends, selling his books and storing away his mementos. Even in those days of 2120, a hundred and fifty years after the invention of space rockets, room was still limited on the liners. Nelson had ignored the news. With the excitement of the trip home, the bustle and hustle of the takeoff at the spaceport, the acceleration bumps, the moon landing and refueling, and then the jump into the big swim to the red planet, he hadn't given the matter further thought.

When things had leveled off afterward and he had overheard one of the crewmen, a steward named Jack Santos, remarking that "it was about time they junked this dusty old Mars drag," then Nelson got angry.

"That's a lot of Greenface growlbait!" Nelson burst out, putting down the micro-manual on which he was boning up. "A lot of weak sisters who never had what it took to be pioneers ran back to Earth, trying to put the blame on Mars. They try to cover up their own lack of guts by claiming we'll never crack that old Martian science—but we will!"

Jack Santos turned to Nelson. "What's a Green-face?" he asked. "That's a new one on me."

Nelson sat up in his seat, eased the straps that held him down in the weightless cabin. "That's what we high-skyers call the people who come out to the red planet and then want to run home as soon as they find it's no pleasure garden. My dad says they used to sit outside and just stare up at Old Earth in the evening sky. It's a green star, you know, so they got called Greenfaces."

Jack shrugged. "Well, whatever you call 'em, I don't blame 'em. There's no place like Earth. But I don't think the argument is as simple as all that. The fact is that Mars hasn't paid, that it's costing a fortune every minute the colony there is kept up and that there isn't any sign it'll ever pay off."

"That's right," another passenger chimed in, an astronomer en route to an asteroid observatory. "Even if you people did crack the mystery of the Martian machines, it'd probably not pay back half of what's been spent. I'm sure we can invent anything they had long before you can figure it out."

Nelson looked around. The living space of the liner was limited, a standard in all such vessels. In this chamber, which did duty as a passenger lounge, there were about a dozen hammock-slung seats, crowded closely on walls, floor, and ceiling, racks of video screens, 3-D tape projectors, micro-readers, and so on. About a half dozen passengers were present, all now listening to the discussion. Nelson realized that he alone was in favor of the colony's continuation. He rose to the odds.

"We'll never invent what's on Mars for another ten thousand years!" he declared. "Why, you can't imagine the things that are there, in the storerooms, in the houses themselves, the constructions, the—oh, you can't just describe it all. If it takes a couple more centuries, we still ought to stick it out and work out the principles of those engines. Just one of them in working order would boost our civilization on Earth tremendously!"

The steward laughed. "But you've never cracked even one of them ... in fact I understand you can't even open the clothes closets in Martian bedrooms! In a hundred years your father and his friends and the ones who went before him never even made a dent in the problem!"

"Besides, we've already taken samples of those machines back to Earth. We can work on them at our leisure without going all the way to Mars to do it," said another passenger.

"How do you know they'd work at all back on Earth?" asked Nelson.

Jack Santos had been fiddling around with a video and finally seemed to be getting results. No one answered the last question as they watched the screen light up and the tridimensional picture waver into reality. Jack worked the hand dials carefully. "We're very nearly out at the limit of visible reception," he announced, "but sometimes we can get a period of good vision."

Sure enough, the set which had faded out yesterday as the liner had passed the five-million-mile mark came to life once more. For a few brief minutes the illusion of looking from a balcony into a living scene came into being. They were looking down on another session of the Earth experts. By a clever system of montage both the audience in the seats of the great assembly and the pulsing face of the speaker could be seen. He was talking rapidly and energetically.

With a little start Nelson realized that the Martian colony's maintenance was still being discussed. This debate had lasted much longer than in the years before. Nelson felt a trifle uneasy as he wondered whether this time they might actually vote to cut down or scrap the Martian settlement.

He thought of his father, the renowned leader of the research base there, John Carson Parr. He remembered how many times, as a boy at the dinner table in their sealed-in home in the eerily empty Martian city, his father had explained his hopes of what wonders they would uncover there.

The video wavered, flickered, and went slowly out. Jack Santos flicked off the power. "Out of range again."

Nelson leaned back thoughtfully. He recalled how he had first felt when he landed on Earth, the strangeness of it all. He knew he was unusual in being one of the very few people actually to have been born on Mars. Colonists usually went back home before they raised families, but John Parr and his wife were made of sterner stuff. They wanted their children to be true Martians and so Nelson had actually been born in the little hospital that serviced the entire small colony. To him the lighter gravity was the normal one, and the day he landed on Earth had been a very hard one.

Because he was used to weighing so little, his muscles had never developed the normal strength of an Earth boy's. He had spent his first few weeks on Earth simply learning all over again how to walk, how to breathe, how to carry his weight around all day. But he had come through the ordeal. His heritage as a human had proved capable, and before he was on Earth six months Nelson had been able to hold his own with the best. As he had gone on with his studies, as the first year went into the second and third, he had even begun to acquire a high standing in sports. He had gained a place on the Institute basketball team, had won track contests, and was a strong contender in tennis and other games requiring bodily speed.

When, at last, he had come to the spaceport to embark once again for home, he was a bronzed, tall, muscular young man of sixteen, with an unruly shock of chestnut hair, sharp green eyes, and a special zest for the part he planned to assume as a true high-skyer.

As Nelson mused about the takeoff day, he remembered that the famous scientist Leroy Perrault had shown up unexpectedly to say good-by to him. Nelson had been quite surprised, for he had met the savant only once during his entire stay on Earth and certainly did not consider himself important enough to warrant a personal farewell. He knew that Perrault was a good friend of his father, a strong supporter of the colony, who held some sort of position in the Interplanetary Bureau, exactly what he never quite ascertained. Still. . . and then Nelson flushed inwardly as he remembered that the keen-eyed old man had indeed had an ulterior motive. When Perrault and young Nelson had momentarily been out of sight of others, the scientist had hastily taken a letter from the inside pocket of his coat and slipped it into Nelson s hands.

"Give this to your father as soon as you land. Don't let it get out of your possession until then. It's important!" Perrault had whispered this to Nelson as he guided the letter out of sight in his clothes.

It dawned on Nelson then that he had forgotten all about it in the excitement of the takeoff. A chill ran up and down his back for a moment—where was the letter now? It must still be in the pocket of the jacket he had been wearing at the time. And that jacket was hanging right now in his little cabin locker, unguarded and unwatched!

Nelson unstrapped his seat belt, murmured an excuse to the others present, and kicked himself away toward the corridor leading to the sleeping quarters.

Although there were several theoretical ways of supplying an artificial gravity to a spaceship, none had ever proved practical on a long-run ship. All interfered with observation and direction, all compelled the ships to assume odd and difficult shapes, all made it impossible to make landings and takeoff s in a single vessel.

The original dreamers who planned spaceships in the ancient days of the twentieth century before even the moon had been reached had cooked up elaborate schemes for planet ferries, subsatellite way stations, and circular liners that would themselves never touch the surface of any world. Like all such paper schemes, these had proved entirely impractical. The practical spaceship had to be able to land and leave its destination in much the same way that the practical airplane and boat had to. This, when space is involved, meant no gravity when aloft.

So Nelson Parr swam through the air of the corridor like a large ungainly fish swimming through transparent water. Out of the circular passenger room, past the bulge of the forward gyroscope compartment, and into the short passageway lined with the doors of the tiny sleeping compartments. To his surprise the little hallway was dark.

As the lighting was from permanent atomic bulbs, this was entirely unexpected. Somehow the bulbs must have been shielded, perhaps even broken. It was pitch dark. Nelson groped for the door to the gyro room behind him, swung it open. The light from there cut into the short hall, lit it dimly.

Nelson pushed off toward his own compartment. He bumped against it as the door to the gyro room swung shut on its automatic springs. Nelson groped for the handle to his door, found it ajar. He pushed against it, floated into his quarters.

The light was out here too, but the tiny space porthole was unshielded and the sharp cold glow of the stars pierced the little chamber. For an instant Nelson saw a dark bulk loom across the limited view. Then he was thrown back as a heavy weight flung itself at him, shoved through the door and hurled itself in the direction of the crew's quarters.

Nelson yelled "Stop!" and threw himself off the far wall. He plunged through the door into his own cubicle just as the flash of light in the hallway showed that who ever it was who had been snooping had escaped into the next section of the liner.

Regaining his feet, Nelson reached for the ceiling light, flicked back the plastic hood which was the only means of turning off its permanent glow. The soft atomic whiteness illuminated the little compartment. Nelson squeezed himself down on his bunk and looked around.

Clearly the place had been the subject of search and clearly the probe had been interrupted before it had been completed. His valise was open, its contents scattered. A drawer in the wall was open and disarranged. The mirrored door to his little washstand was ajar.

Nelson stood up, opened his locker. His jacket, coat, and spare clothing still hung there, apparently undisturbed. He reached into the jacket pocket and to his relief his fingers touched the surface of the envelope. He withdrew it, looked at it.

It was just an ordinary mail envelope, thin opaque plastic. Across its face was written his father's name and the word Urgent!

Undoubtedly it would have been discovered had the searcher had but a few more minutes. What that would have meant Nelson had no idea, but he made

their way up to something like civilization. There had been no evidences of intelligent life on the other worlds.

The pitifully narrow twilight belt of Mercury, with its violent winds, now oven-hot and now icy-cold, harbored the lowest type of rock-clinging moss and deep-rooted cactus only. The crater bottoms of Luna, where a thin atmosphere sometimes gathered in the heat of the sun, had fast-growing and fast-dying crops of green stuff, part vegetable, part something else—but not animal. Two or three of the larger satellites of Jupiter had tough hardy forms of plant life, and even a few very queer and sluggish animal forms fighting for a foothold against the intolerable cold at that distance from the sun. Farther out from Jupiter, the worlds wheeled cold and lifeless, brilliant and changing perhaps in their chemical and crystalline reactions, but sterile nonetheless.

There was always Mars as the holdout. But the intelligent life of the Earth's neighbor was a mystery—a dead mystery apparently. There had been intelligence there, yes. A wonderful, tremendous, brilliantly skilled intelligence. But it was gone totally, save for its works. And despite all the decades that men like Nelson's father had spent exploring there, they did not even know exactly what the Martians looked like.

Except for one factor—they must have resembled men. Their homes and belongings seemed designed for manlike beings—and Nelson remembered that the Martians had a hand with five fingers, as the handgrips on certain instruments had proved beyond doubt.

But that left no known race to account for this print.

Nobody on any world known to man had a three-fingered hand of such a curious pattern! Perhaps, thought Nelson suddenly, the explorers had been mistaken about the Martian hand? Perhaps this was the true appearance of a Martian's hand? Perhaps then the Martians were not extinct . . . and one of them was here, on board the Congreve, returning home.

That raised another thought. Returning home from Earth? And what had it been doing there?

Nelson stood up, patting the place in his suit where he had hidden the envelope Dr. Perrault had addressed to his father. This must have considerable importance to attract the attention of such a spy? What was up? Well, he'd find out in time. Meanwhile he would have to take great care not to be caught off guard.

He went out of his compartment, closed the door and made his way back to the passengers' chamber. He noticed as he did so that the lights were again unshielded in the corridor. As he rejoined the company of his fellow passengers he debated the course he should take. Should he tell people about it, ask for help on a search? Would they believe him?

He decided they probably wouldn't. Merely because he had seen what he thought was something odd on his mirror, something that had since disappeared, they wouldn't get excited. After all, nothing actually had been taken. A search might simply cause the unknown to keep under cover.

What he had to do was to keep an eye on everyone. Obviously whoever it was must be wearing artificial flesh-simulated hands. It would be fairly easy to make a pair of gloves designed to look and feel just like human flesh. A three-fingered hand would fit into such a five-fingered glove so that none might suspect the trick. Yet, Nelson supposed, it couldn't be quite as flexible as a human hand—or could it? He would study everyone's hands for signs of strangeness.

He observed the passengers. He watched the crew, making special excuses to cover even the men on duty in the atomically dangerous feeding-chamber room. But it all proved futile.

Wait as he did, there never seemed to have been another attempt on his room. Despite careful arrangements of his drawer to show whether any disarrangement took place in his absence, he found nothing. Watching hands for clumsiness proved quite difficult when most people did very little save sit and read, watch canned-shows, or stand duty.

Time dragged on, as it does on even the speediest space flight. The flight to Mars from Earth had once taken one and a quarter years each way. That was in the old days of the chemical-type rockets fueled and launched from the Lunar base, after other big rockets had ferried the riders to the moon. The time had been cut as the development of atomic fuels had been perfected. It took longer than had been supposed, but with the perfection of direct application of atomic reaction to space flight the ability to accelerate for long periods of time was vastly increased.

The speed of a spaceship depends entirely on how long a period rocket acceleration can be kept up. As there is no friction in the empty voids between the worlds, once a speed is reached, it remains the same unless deliberately countered and slowed by an opposite rocket action. But the amount of acceleration depended on how much fuel a ship could carry. Where chemical fuel was concerned, the weights involved were so enormous and the results actually so weak that, from a celestial viewpoint, the speeds were very, very slow. But atomic power can produce tremendous volumes of energy from very little bulk. All that had to be discovered was a means of liberating it which did not involve massively heavy shielding and massively heavy piles. That final discovery did not occur until space flight was already well under way.

The trip to Mars now, while the planet was at its nearest orbital point to Earth, was a matter of about three weeks. In that time one had to amuse oneself as best one could. Space on a ship, even the largest finer, is limited. The grand sight of interplanetary space as seen through the ship's thick but crystal-clear portholes was always breathtaking, but essentially unchanging.

Nelson, like the others aboard ship, made a point of looking toward Mars the first thing on arising each ship's morning. The red dot grew slowly, taking on a disklike appearance that gradually became larger and began to show surface markings. The orange-red "star" became a russet-yellow disk with a visible white spot that was the icecap of the North Pole, the frozen surface of the ancient world's last two large bodies of water—the South Pole being the other.

In time, faint bluish-green discolorations could be noted against the surface. These were the fertile lands, the large oases where the land of Mars had not yet dried and where grew the prairies and forests. The explorers of Mars had come to consider these regions as the "continents" of the world, separated from each other not by seas of water but by seas of desert. By far, most of Mars was desert—endless reaches of rusty rock, barren waterless plains, great stretches of slowly shifting yellow sand or reddish dry dust, and occasional very low stumpy lines of mountains, worn down to be little more than ridges above the general flatness, for there were no true mountains on Mars. No mountains, no lakes, no rivers, no rains. Once in a very great while, so rarely that Nelson had seen only two in his dozen years of life there, there were clouds, white clouds moving slowly across the deep blue sky.

And there were the Martian structures, the means by which the continents of vegetation kept alive. But they could not be glimpsed from space, not until perhaps the very last day.

The ship decelerated and Nelson was no closer to the solution of his problem. There were strange characters among the crew—but then there always were. The silence and eeriness of space flight always produced quirks of character among the professional sailors of space. Nelson could see nothing in this to arouse real suspicion.

On the last day there was too much excitement to pay any further attention. The ship was decelerating fast, under full engine power. Gravity was thus being simulated and it was hard to get around, for the drive was often against the normal setup of the compartments and rooms. Passengers were packing. The crew was tightening up the ship for the landing. Then the order was boomed through the liner to buckle into safety seats, the pressures grew, and the ship battled its way down.

About the hull arose a thin hissing and then a roaring as they tore into the Martian atmosphere. The ship heeled and jerked as the pilot kept it steady. Finally after an hour's breathless fall the ship eased to a complete stop and settled softly to the surface of the Martian world.

Nelson unstrapped himself from his seat. As he stood up, he suddenly felt a surge of strength. The four years on Earth had built up his muscles to resist a far heavier gravity. Yet something in his body reacted with pleasure. This he felt was home. His body relaxed into the familiar patterns of his boyhood and he knew what he had been missing for so long—the gravity of Mars was the pull of his own world, the planet to which he had been born.

He packed his possessions into his valise, left his compartment and made his way to the exit lock, before which other passengers were waiting. As he caught sight of them, his hand thrust once more underneath his shirt to pat the envelope that was safely there.

The exit opened at last and Nelson made his way through, down the metal ladder that had been run up by the outer attendants and stood once more on the rocky surface of the planet's sole operating spaceport. Someone in the crew called to him but in his excitement he paid no attention.

He looked around. The corrugated iron shacks beyond the area of landing looked as old and ramshackle as ever. Great glassy areas marked where the atomic blasts of liners had fused the desert surface. On three sides of the field stretched only the great desert. On the fourth side a line of blue-green showed where the edge of the Solis Lacus oasis started. Stretching toward it was a white plastic road, one of the very few manmade structures on the planet, the road that connected the central city of Solis Lacus with the spaceport.

Nelson started toward the shack where visitors waited. He walked with an easy springy step that carried him yards at a time. This was Mars, where he weighed only forty-five pounds though muscled enough for a hundred and twenty. A small group of colonists were waiting there patiently. Among them Nelson thought he glimpsed his father's gray head.

But as he went, he began to find himself gasping for breath, felt himself becoming dizzy and faint. He stopped, put down his valise, squatted by it. He had forgotten his respirator!

If his fellow high-skyers had seen him, they would have really ridden him. For all his training, he had forgotten the one thing that every colonist makes second nature. The air of Mars is thin and low in oxygen. A man had to wear a mask and a little shoulder pack that would suck in the air and pump it into him in greater quantities than his terrestrial lungs could do. Otherwise he would blank out for lack of oxygen.

Nelson opened his valise, fumbled in it, took out the little pack. Hastily he strapped it on his back, high between his shoulder blades and adjusted the transparent plastic mask over his nose and mouth. The little silent engine on, he felt a rush of air to his nose and mouth, felt his senses clearing as his lungs received the oxygen to which they were accustomed.

Nelson stood up. Other passengers were beginning to overtake him. He picked up his bag and again went on his way.

In a few moments he was embracing the tall form of his father, exchanging fond words. John Carson Parr smiled at his son from deep-set blue eyes. His bristly shock of iron-gray hair, his dried long-boned face, his lank Lincolnian body, were all as Nelson had remembered them. Old Parr slapped Nelson on the back. "Gosh, it's good to see you, son. Have a clean trip?"

Nelson was about to mention the incident of the intruder, then decided to find a better time. "Sure, we made it all right, no incidents, no meteors, no comets. And," he continued, "I have a message for you from Dr. Perrault."

John Parr's face became serious, his eyes flickered. Nelson took out the precious envelope, gave it to his father. Parr looked at the cover with its Urgent on it, then, instead of opening it, slipped it into a pocket.

"Let's wait until we get out of here. After all, your mother and sister are anxious to see you."

They slipped out of the small crowd and made their way behind the landing field shack. There Parr's three-wheel jet car waited. They climbed into the little bullet-shaped vehicle, and the elder Parr pushed the starter button.

The little craft whizzed off down the thin white road toward the line of vegetation. Its controls auto

discoveries. For the secrets of Mars would enrich mankind a thousand times over!

"Surely, Dad," Nelson finally broke the silence in the speeding car, "they won't entirely empty the planet? They'll leave some explorers to keep up the search. Surely you'll stay and . . . and Worden and maybe McQueen and others like them; men who really know this world and can work on."

"You would think so, son," said his father, his eyes staring straight ahead at the thin white road. "But they've decided otherwise. As a matter of fact, they've been preparing for this for several years now. They've been drawing in the posts, calling back the explorer crews, sending people home steadily. When you left for school there were about three thousand people here. You may be surprised to learn there are only about three hundred here now. And in about three months we'll all be gone. Every single one of us."

Nelson jerked his eyes away from the rolling fields, and the thin webwork of Martian pipelets that covered them so exacdy and so unbreakably. He stared at his father. "You mean even the South Polar diggings have been stopped? And the work in the Syrtis Major vaults . . . that too? Why, they'd been well on their way to breaking through into the main chambers! That alone might have solved everything."

"The polar diggings were shut down over a year ago," his father replied. "As for the Syrtis excavations— I'm afraid they weren't panning out any better than all the rest of our operations since we first landed here. They had gotten around to using atomic blasters on a small scale and they couldn't budge the walls. No, I don't think they'd have gotten through in any short time. But that's over and done with. Worden came back with his crew a week ago."

The young man pounded a hand into his fist angrily. "Can't we refuse to go home! Can't we just stay anyway!"

John Parr smiled a little bit, glanced at his son. "You know it would be impossible. With the winters here, with our need for steady shipments of the vitamins and food products we can't seem to raise from the Martian crops, we couldn't survive for more than a couple years. Not as a colony. And as for leaving just a few men, why, we'd be so busy just keeping ourselves alive we'd have no time for anything else."

The two rode in silence again. The little tear-shaped car was approaching the city and the sight was always one that made every Earthman silent with wonder. A Martian city is something like an iceberg on a terrestrial sea . . . about one-tenth aboveground and the rest below ground. But that one-tenth itself was something. A vast area of low rounded domes of many colors, rising from the ground like thousands of half-buried billiard balls. Separating each a profusion of greenery, thicker than even in the fields, the strange piny growths of Mars, thick like cactus, curiously movable on their short chunky stalks, folding themselves into tight variously colored balls at night like a forest of lollipops; unfolding in the weak sunlight to reveal thirsty blue-green spiky and furry leaf interiors. There was something about a Martian city that resembled nothing so much as some of the pictures from quaint old folk tales of the homes of trolls and pixies.

These domes were homes, sealed homes. Beneath them extended a tremendous series of catacombs, chambers, tunnels, going far down into the soil, sometimes a mile down, and in these hidden works lay the heart of the city, the business, the factories, the centers of the lighting, heating, watering, air conditioning. There somewhere must be underground trains or their equivalents, connecting links between all the hundreds of similar cities of Mars. There must be hidden their museums, their records, their libraries. And in a dozen Earthly decades, no human being had done more than walk the barren halls outside the doors of these places. For Mars was a sealed world. And there was no visible key.

It was lucky for the first men to reach Mars that the domes on the surface were open. Their curiously rounded doors, set flush in the surface of the solid seeming domes opened at a touch. Within these domes were the chambers and rooms of habitations—the homes of the vanished Martian population. That they were such was plainly to be seen. The Martians, whoever they were, had not been very different from the men of Earth, for there was little to suggest that men had not lived in those homes. They were the right size for men. They were fitted out as men would fit out their homes, there were recognizable kitchens and bedrooms, rooms that must have been for pleasure and living, rooms that may have been for games, rooms that could have been nurseries.

From within, the walls were invisible, like trick mirrors, those within could see out, could see the light and the flowers. But from outside, the walls were solid, did not transmit vision. There were floor coverings, as beautiful and soft underfoot as the finest of rugs, and they could not be removed from the floor. There were frames on the walls which held blank spaces that might have once been pictures or television scenes or projections, but whatever activated them could not be found. There were all the closets which could not be opened and for which no key or opener could be found. There were cooking machines which could not be made to function. There were air-conditioning, heating and cooling units in each house, built in, which did not function. There were openings which may have been faucets, but from which nothing could be induced to flow.

As Nelson and his father stopped their car before the soft blue dome that had become the Parr residence, the door flew open and a middle-aged lady popped out with a little girl at her heels. Without their respirators, Nelson's mother and sister could not wait to welcome him home. The two men jumped out, and, after a few excited minutes, Nelson found himself back in the main room of the dome in which he had spent his childhood. He looked about him, recognizing the familiar scenes of his boyhood.

But now he took notice as he had never before of the things which alone made this place habitable. Though there were vents for air conditioning, there was an atomic heater of Earthly make that kept the room warm. Though there were areas in wall and ceiling which must have been sources of light, the only lighting in the room was an openly visible system of wiring attaching to a normal Earthly bulb. He knew in the kitchen the Martian stove still stood silently mysterious while his mother cooked their meals over an imported and too-small aluminum burner. He knew in their bathroom they would wash as always with a limited quantity of chemically purified and constantly reused water from a small tank clamped unbeautifully to the Martian wall.

Although there was a closet in his bedroom, Nelson did not attempt to hang his clothes in it after unpacking. For the closet door would not open and never had been opened. Instead, he hung his clothes in the thin plastic-board folding closet that had been brought from their home world several dozen years before.

He returned to the main room, sat down to his first meal at home in four years. The talk was about the evacuation of Mars. Suddenly Nelson realized that his mother and sister had known about this for several days. A thought occurred to him.

"If this evacuation is actually old news to you, then what was it that Perrault had to tell you?" he asked his father during a lull in the conversation.

John Carson Parr looked at him sharply. "Why, that had to do with something else. Nothing of importance," he said, glancing at his wife and daughter. Silently he shook his head as if to warn Nelson to say nothing further on the subject.

Nelson wondered about that letter often in the days that followed. But the matter of removing the Earth colony was not a simple one. Everyone's time was occupied. During the next few days a great fleet of spaceships and liners and freighters put down on the desert surrounding Solis Lacus. Besides the Congreve, the other liners of space, usually on duty nearer the sun, came down from the deep blue sky and perched upright on the sand. The Goddard, the Pickering, the Valier, the Ziolkovsky, the other liners of the type arrived. And the freighters came in, some of them fresh from storage on Earth, as the mining developments had come to a halt following the synthesis of elements on Earth. Nelson was amazed to see ships bearing the colors and emblems of the long defunct trading companies that had originally built up the once lucrative asteroid trade.

Then there was the problem of assigning space to the three hundred remaining colonists. Spaceships never had too much cargo room, and it would take just about every inch to transport the men, women, and children safely. Very little of their personal possessions could be taken. They would have to leave things like furniture and excess clothing, books and radios, cars and planes behind. But then, most of that material was made to suit the rigors of the Martian climate, a world where in midsummer temperatures might reach the seventies and yet plunge to thirty and forty below zero by midnight. Where in winter the temperature at midday would never pass above zero and might drop to a hundred or more below by nightfall. A world whose air was too thin to support planes built to Earthly designs and yet would fly planes too wide-winged and weakly powered to operate in the thicker air and heavier gravity of Earth.

Nelson and his father and his father's associates in the leadership of the colony were busy listing available spaces, assigning families, seeing that they were stowed aboard and that the ships took off for the green-glowing evening star as fast as they were completely booked. They had to settle arguments as to what could go and what could be left behind. They had to arbitrate between people who insisted they had not enough room or were separated from their friends. They had to console weeping mothers who did not want to leave their homes, even on this alien world, to make new starts on what would be to them a very strange and hard planet. All had been promised good homes and jobs, but it was nonetheless exile.

Through all this, Nelson worked and watched with a heavy heart. As each man departed, as each ship roared away into the sky never to return, he knew that mankind had lost another chance to open up a treasure house that had no equal in history. For they left Mars almost as mysterious as they had found it.

Mars was a complete world, a world which had known a tremendous and far-advanced civilization. And it had been sealed up by its original people, sealed up and abandoned with its basic organization still running.

An old world, Mars could only keep its areas of plantation and vegetation going by piping the waters from the poles as they melted during the summers. To do this, the Martians had built up with heaven alone knows what tremendous effort and ingenuity over what must have been tens of thousands of years a world-wide system of irrigation. Webbing the planet from pole to pole were the great viaducts and underground sealed currents. Pumping stations operating no one knew on what power source kept the waters moving uphill against the gravital pull from the poles to the higher regions of the equators. The vegetation growing in thin strips alongside these lines had allowed even pre-rocket astronomers to see them, to map them, even to name them as the great Percival Lowell had done as far back as 1895. In the great continents of blue-green trees where the Martian cities had been found, these conduits alone enabled the planet's plant life to continue on a world otherwise without rain, river or well.

And it was all sealed. The colonists had found Martian machines plainly designed for land travel and air travel, but they could find no way of activating them. The power source was a mystery. Theory said that somehow the Martians must have broadcast their power from central stations, and these machines picked up their energy like a radio picks up a program. But where the power-sending stations were no Earth explorer had ever found out.

The Martians had used their thousands of years advancement to produce locks and metals that resisted all efforts to crack. A closed Martian door, such as lined the endless underground corridors and halls, simply could not be opened. Drills could not scratch their surfaces, explosives could not mar them, atomic reactions could not shake them or dent them. They had resisted successfully the best efforts of the best scientists of Earth.

Nelson knew that if they could but once get past these doors, could but once explore the factories and machinery behind them, they would be able to make the planet live again. They could make the dome houses naturally habitable. They could fly the hundreds of thousands of Martian vehicles that were plainly available in garage domes everywhere. They could get into the libraries of the vanished Martians and enrich their knowledge of the universe a thousandfold.

They had had over a century to do this—and they had failed. Mars was like the legendary ship, the Marie Celeste, the ship that had been found in the Atlantic, sailing along, its table set for lunch, its boilers still warm, the log open on the captain's desk awaiting a note, its lifeboats still hanging, its crew's clothing still in place, and entirely empty of crew. Without reason or cause, its crew had vanished into thin air.

And there was the case of the famous city of Angkor deep in the jungles of Indo-China. A great city, the capital of what was once a great empire, simply abandoned, its population departing en masse into the jungle, taking nothing with them, not even their possessions.

And that was Mars. Where its people had gone to, nobody could imagine. They had simply vanished. They had taken nothing with them, except perhaps their clothing, for their homes were untouched, their cities still intact, undamaged, their agriculture still automatically functioning, probably their entire planet ready to resume full life once someone could find the controls. They had left no pictures of themselves, no statues, no inscriptions that could be read. They had left no bodies, no skeletons, no cemeteries. Possibly there were some somewhere, must be, Nelson had always thought, but to find them in this world of desert would be sheer luck. And there had never been enough explorers here to warrant such a stroke of luck yet.

Now there never would be, probably. Nelson's thoughts were glum as he finished packing the very valise with which he had arrived. Their day had come. Only one ship waited for the last members of the colony. Out at the spaceport, it was already two-thirds full, and now only the Parrs and his father's immediate associates were awaited. After them, there would be nobody else. The planet would be as empty of human life as it had been before the first ship had made its wild rocket-driven landing so long ago.

Outside, his mother was already in the little car. Nelson went through the dome house, mentally saying good-by to the scenes. His little sister came out tearfully from her room clutching her favorite doll. Tearfully she kissed it and set it up in a sitting position on the floor of the living room. It, too, was excess weight. Then with a sob she ran to join her mother. Nelson followed his father through the door, adjusted his respirator mask, and swung the rounded door shut. It clicked tight, adhering with that fine keenness of Martian architecture to the surface of the blue dome. The two males piled into the car, started the engine.

The trip to the spaceport was made in silence, as each strove to imprint on his memory their last glimpse of what they had regarded as their home world. At the spaceport, they were checked off by the ship's captain, their baggage taken from them and sent up to their space.

John Parr turned to his wife. "You and Beth go aboard to our cabin. Nelse and I want to talk a minute with Worden before we join you."

Nelson's mother nodded and, casting her husband and son a strange long glance, took her daughter's hand and went off to the ship. As they went, Nelson felt his father s hand close on his arm. "Stay close to me," he heard his dad whisper.

A sudden thrill ran through the young man. He turned. In the little space of the corrugated-roofed spaceport house, there were now only the captain, a crew member of the liner, and his dad's assistant, Jim Worden, the thirty-year-old explorer. John Parr waited until the women had vanished into the distant liner and the captain and his crewman were starting to leave.

He nodded to Worden, and started to walk slowly toward the ship, letting the two crewmen get well ahead of them. The three Mars colonists walked slowly, as if reluctant to leave.

Nelson saw the captain reach the entry port with his man and look back. The Parrs were coming, he could see, for Nelson saw the captain vanish into the space lock. Now his father began to rush, and Nelson and Jim Worden followed him fast. At a point nearly below the ship, out of sight of anyone in the ship, they dropped to the ground.

Nelson watched Jim frantically searching for something. He touched a little projecting knob in the blast-scarred surface of the field. A small circular trap door opened.

"Quick!" breathed the elder Parr, and Nelson needed no second word. Jim was scrambling down

things to be placed in a special file of their own. During the past few years, some attempts have been made to interpret their meaning.

"As a result of this study, it was found advisable to create a special committee to check the whole problem. This committee had to remain extremely secret, a small group of Mars specialists, reporting only to Perrault himself on Earth, who is responsible directly to the President of the Interplanetary Institute."

"Your pop is the head of the committee, Nelse. And now that he's told you I guess that makes you a member, the sixth member."

"Yes," broke in Nelson, impressed but still baffled, "but what exactly are we looking for? What sort of things were discovered to make all this necessary?"

Parr pursed his lips, took a sip of his drink. "Actually, it's hard to define them. If we had to write them up for the papers, probably they'd be laughed at. At first we used to think they were just accidents or mistakes. You see sometimes it would just be that things were displaced. A group of Martian cars in their garage, for instance, might be lined up in a certain way, just like the Martians left them. The next time an explorer happened on that particular garage, it might turn out that the cars had shifted positions. That maybe one was slightly out of line or reversed."

"You could figure that some other explorer had come and shoved them around trying to make one go, only the records showed unmistakably that nobody had been there between the two visits," said Worden.

"That's right. We'd check carefully and could prove that nobody, that is nobody known to the colonists, had been there. Or we might find footprints in the soil outside a dome house where no one was living. Never could trace the prints, never could find anyone who'd admit having been there," said Parr.

"For instance, once, about two, three years ago," said Worden, "while I was flying over a polar icefield, I saw tracks in the ice, newly made apparently. Looked just like landing skids for a small rocket cruiser. Only there wasn't any such rocket around, and never had been. That sort of thing makes up the bulk of the observations. You'd find landing tracks in the desert while flying over it. Sometimes see dust marks on the top of a main conduit far from any settlement."

Nelson was beginning to feel little chills go up and down his back as he listened, and then whispered his thoughts, "You mean, as if there were Martians still around, hiding, peeking out, keeping out of our sight?"

His father nodded. "It certainly seemed like that. And when the information was all gathered together, it looked fairly certain. Something else was here. Something awfully careful to keep out of sight. Something sort of spying on us."

"But that's terrific!" said Nelson. "That means that there's another intelligence other than men around!"

"That's jumping to conclusions too soon," said his father, "but in view of what happened to you on the Congreve coming here, that might well be."

Worden looked up. "What's that? What happened?"

Nelson explained to him. He told him about the attempt to steal Perrault's letter and about the mysterious three-fingered handprint he'd seen. His father had expressed no opinion when he had heard of the affair, and Nelson had wondered at that then. Now he understood.

Worden leaned forward. "What did I tell you, John," he said. "Didn't I say that whoever was spying on us would probably have snooped on Earth too? If this three-fingered stranger was aboard the Congreve in a perfect disguise, then he had come from Earth, didn't he? So they must have some agents there, too. In fact, I'd sometimes wondered if some of the talk about how expensive it was to keep the Mars colony going wasn't traceable to something like that. Suppose these really are the Martians, a few of them hiding somewhere here. Naturally they'd want us to leave. So after they manage to learn to disguise themselves well enough, they could even try to do their share to boost any suggestion that we go home. I don't suppose they could get into the government, but maybe they could pay for a few magazine or newspaper articles here and there to keep the idea of abandoning Mars in the public eye."

John Carson Parr shook his head. "That's too much speculation. There isn't really a shred of evidence that the leaders of the Greenface movement are anything but honest in their views. Anyway, it's futile to discuss it. The evacuation of Mars is complete. Now it's up to us.

Nelson didn't know just what was up to them, but decided to wait and see. Meanwhile they unpacked their equipment, stuff that Worden and Parr had moved there during the last month in preparation for this. They spent the rest of the day sorting it out, settling down to wait for the rest of the committee to come out of hiding and join them.

By the next morning, burly Bryan McQueen turned up, trudging along a corridor from the city. A big man, he was an authority on the deserts of Mars and had spent most of his living years traveling alone over their vast reaches in an enclosed sand-walker or skimming their surfaces in a slow plane.

Two days later, the remaining members of the committee turned up. These proved to be Francisco Jose Gutman, the famous botanist, and Karl Telders, the noted interplanetary engineer and rocket expert. And then the waiting was over. They were all there, the last men on Mars.

As soon as these last two joined them, they packed their belongings again, strapped what they could on their backs, and started off down the tunnels. Following a path mapped out by Worden, who had thoroughly explored the regions beneath Solis Lacus, they wandered in and out of the labyrinth, until, to Nelson's surprise, just when he had thought they were surely lost, they climbed up an incline, went up some metal steps and he poked his head out the round door into the basement of his own blue-domed home in Solis Lacus.

During all this trip none of them had been seen aboveground. Nelse knew that they were to keep their presence a secret. Their game was to keep watch and tape that the mysterious strangers would venture forth in plain sight when they were convinced that the planet had been abandoned.

Once in the comfort of the former Parr dome, they held a council of war. John Carson Parr pulled a new surprise out of his pocket.

"Now that we are all here, it may have occurred to you that it would be almost impossible for us to do any spying ourselves and hope to see our quarry. After all, if we have to keep out of sight, we too must remain out of the air and off the roads. If our Martians chose to come out and set up shop in some oasis half the planet away, we might never know it. We certainly couldn't observe it. Again, if we do spot them, and they spot us, they would quickly realize how few we are. It would be very easy for them to attack us and wipe the six of us out."

The rest of the men nodded as the logic of this became clear to them. After a pause, the gray-haired explorer continued, "So we are not going to stay on Mars at all. We are going where we can watch the planet as much as we like and yet not be seen. We are going where we can see all parts of this world regularly, check and recheck, without danger to ourselves."

Gutman raised his eyebrows. "And where would that be, John?"

Telders spoke up. "I know. I can think of only one place—or rather two places—for that."

"And where would they be?" said McQueen, swivel-ing in his chair.

Telders merely smiled and gestured a thumb upward. McQueen followed his gesture, puzzled. Nelson spoke up slowly, "Do you mean the moons? Phobos and Deimos?"

His father nodded. "That's it. We're going to Phobos and set up our observation post there."

"But where's the ship for that?" asked McQueen, still perplexed.

sity to which his colonial training school back on Earth had been affiliated. Stuck on the wall in other places were relics of his Martian boyhood, a crudely hand-printed banner of the Solis Lacus General School—the only grammar school on all of Mars. There was a telepaper fix-photo of his father receiving an award for some special research on the desert flora— those queer gray stumpy plants that popped up unexpectedly in odd places of the iron-red barrens. There was a Martian root crawler, one of the few native "bugs," which Nelse had caught and mounted himself in permanent stasis by means of perfect sterilization of its body cells under a light atomic beam such as was used for preserving meat. Other objects, such as his jumping rod; his spare respirator, too small for him now; his lacrosse stick; and so forth, all of which had been dear to him.

Nelson turned over, closed his eyes.

Before he knew it, the whistling of his alarm brought him to his feet. Outside, the sky had turned to a deep blue-black and the sharp bright stars that shone through the thinner Martian atmosphere were burning whitely, as they had never done on Earth. The bulbs in his room were glowing pleasantly as he pulled on his shoes. He caught a glimpse of a tiny crescent moving slowly through the dark sky. That would be Deimos, the smaller moon.

He joined the others of the party. They raided the pantry left by Nelson's mother and had their last meal on the red planet. There was a good store of food, abandoned like all the rest. When they finished, they donned their respirators, pulled on their night coveralls—electronically heated garments for the cold outside—pulled the hoods close over their heads, settled their packs, and followed Worden down again through the trap door in the Parr home.

Now they made their way through the old passages under the city itself. Though there was probably some sort of native lighting, none of it worked, dead as the rest of the planet's mighty civilization, dead or in cold storage. Beneath the city itself there was such a web-work of passages, doorways, entrances downward and exits upward as to leave almost no lengths of corridor. Nelson, who had visited the underground ways of terrestrial cities, particularly the maze of trains, moving passageways, and foot tunnels, found himself comparing them as he strode along behind the other five. It occurred to him curiously that those Earth cities were somehow so "new" and so "elementary" compared to this. For a moment he felt awe at the thought of what this could have been like, all lit up and filled with hustling Martians.

On they went, following Worden, who had a map of the underground ways that had been worked out by explorers. Every now and then he stopped to check his position, then went on.

After about four hours of steady wandering in and out of the endless catacombs, Worden brought them to a halt. He swung open a trap door above, and they climbed the ladder that rested there.

They emerged into a large dome, cleared of its interior rooms. As he stuck his head out of the trap door, Nelson saw that the dome housed a rocket cruiser. A small duplicate of the great space liner, a craft such as was used for exploration of the asteroids—a clean powerful little craft, capable of carrying them all comfortably, capable of fast flight, and carrying a fair cargo. It was as new a ship as he'd seen, and he realized that it must have been sent sometime in advance for just this type of emergency.

Telders unsealed the single main lock and they filed in. Inside it was just as Nelson anticipated. He had studied space training in a replica of such a craft as this at the Institute. The trim long central and front cabin, the bunks for six lining the wall, the cargo chamber, now holding a number of crates, as well as food supplies. The now fairly small engine space-immensely compact since the recent developments in rocket engineering—the original spaceships had been about ninety-five percent engine and fuel. This one was not more than about thirty percent such.

When all was ready, they checked their watches, and Telders took control.

"All set?" called out John Carson Parr, seating himself in the soft bucket chair next to Telders.

The rest of them called out their readiness. Nelson was near the controls; he wanted to watch through the forward port.

Their target, Phobos, was not in sight. Nelson had not expected it to be. Telders had undoubtedly figured just when it would be overhead and arranged their speed and flight in such a way that they would cross its orbit at the moment the satellite would be there. Their trip might take a few hours, at the relatively slow speeds of near-planet regions. Since Phobos circled Mars in slightly over one day, by the time they had gotten five thousand miles up, it would be up.

"Time!" called out the rocketeer and punched a button.

Outside, the curved dome slid back and the open dark sky loomed over them. For a moment Nelson caught a glimpse of the gray starlit city, its domes cold and dark, the horizon stretching beyond. The ship lifted slowly, pointed its nose at the heavens and climbed, rapidly accelerating. In a matter of seconds the city was a mass of bubbles beneath them, a gem set in the darkness of a sleeping plain of dark blue, whose edges, even at night, could be plainly defined against the glaring lightness of the desert.

Nelson smiled suddenly, oddly, as he looked down. McQueen, near him, said, "What's the joke, son?"

Nelson looked up at the burly engineer. "It suddenly struck me," he replied, "to wonder who else saw us leave."

"Nobody, I hope," said McQueen. "Wouldn't be a smart thing for them to know we're still around."

"Oh, I don't know," said Gutman, glancing down. "Even if we were seen, they'd probably only suppose we were the last and going home also."

"Come to think of it," said Nelson, "we are really the last. There's nobody left on Mars at all. Nobody."

"Hmm," said John Carson Parr, looking thoughtful, "in a way this represents a real defeat for humanity, our first retreat from space. This is the first time in a century that there hasn't been a single Earthman on this world. Though we ourselves may return for a while, right now that world is empty again. As empty as it must have been for who knows how many thousands of our years."

"Ah, well," said McQueen, "we'll return. We've got to. You can't keep an Earthman down for long!"

The red planet receded slowly, its horizon spreading out as they penetrated the now black airless sky outside the atmosphere belt. Covering all the sky beneath them, it seemed like a dark flat surface blotting out the stars. Far to one edge, Nelson could see the rosy glow that was the line of the coming day. The surface of nighttime Mars was not black, seen as close as they were, but shone a dull blue-gray, broken with dark patches where its vegetation continents and canal streaks showed.

The trip continued with little conversation, for every man seemed buried in his thoughts. Nelson watched the sky carefully until at long last he caught sight of the thin crescent that was their destination. He watched it, knowing that the ship and the moon were racing together, apparently to collide.

Now Telders began navigating the ship, changing its speed, slowing it down, bringing it into an orbit nearly parallel with that of the little satellite. They raced along like a small moon themselves, with the larger body coming up fast behind them.

After another half hour, the sphere of Phobos was filling their outer view. Now they had the illusion of gliding along just over it, and Telders skilfully brought the ship closer and closer, changing his speed delicately until at last they were skimming low over a flat rocky plain.

The ship dropped steadily until it seemed to be hanging over the surface, and Nelson could see the small rocks and cracks that marked the surface of the satellite. Now, with ease, Telders brought the ship down and very gently it settled to a landing on Phobos.

They got up from their seats and the sensation was as if they were still in deep space. They seemed to be without weight. "Easy does it," called out John Parr. "Carry yourselves as if in weightlessness. This hunk of rock is only ten miles in diameter. Our weight is in fractions of a pound, don't count on it."

They swung around the cabin, gathering their possessions.

"Everybody know how to use spacesuits?" asked Parr. The question was merely academic. Without further ado, the six of them climbed into the new lightweight, completely pressurized and regulated suits that were a feature of this stage of space-flight history. Nelson had learned the use of these suits and had worn them in space chambers in training. He climbed into his own, tested its fitting, fitted the transparent bowl helmet over his head and heard it click tight to his neck and chest connections. The air clearance valves instantly opened, the helmet radio promptly snapped on, and it was as if he were standing amid his friends in normal surroundings.

"No time to waste," said Parr. "Everybody take a load with him the first time we go out. We'll make this ship our home, but the observatory has got to be outside. Let's get going!"

Nelson took the bundle of tent cloth that had been handed him and, getting in line behind McQueen,

material on a fairly flat space where their observations could be carried on with the least interruption. Although a tiny body, Phobos had the same peculiarity as Luna, in that it did not turn on its own axis more than was sufficient to present the same side to its parent planet. At the spot where the Parr group had landed, Mars was a large ball directly overhead at all times.

McQueen and the rest assisted in putting up the observation shack, wherein the records would be kept. This was built of plastic walls, sealed airtight to each other and capable of holding air within it if necessary. As a rule, however, this shack would house a table, a file, and such records as could be kept in the airlessness of the natural surface. The men who would be on duty at their spotting posts would record their findings without removing their spacesuits.

Before long this shack was up, a special shockproof platform erected beyond it, and the lenses of the telescope mounted on a simple skeleton framework. No mechanical motor would be required to keep the objective in sight, for here the objective was always stationary. Hand controls could sweep any part of Mars in view. And as the red planet rotated on its axis, and Phobos followed its own path, very nearly all the surface would be kept under view regularly.

Radarscopic observation would also be placed in use to register moving bodies across the face of Mars. This probably would not be used except when such mysterious motion was suspected by the observer. Then this device could be focused on the suspected spot and would register the truth or falsehood of the observation.

They knocked off work to eat in the space cruiser. After they had satisfied their hunger and privately rejoiced to find Telders as good a ship's cook as he was a ship's navigator, John Carson Parr called a conference.

"We'll have to set up a regular system of watching crews. Two men must be on duty outside at all times. So we shall divide our day into three sections. Two men asleep, two men in the ship, two men outside. The four men awake will spell each other at two-hour intervals so that no one will be outside in space-suits too long."

"May I suggest," put in Worden, "that perhaps it would save time and trouble to set up a photographic system rather than a human eye system? We do have telescopic cameras aboard and by attaching them to the scope and developing them regularly we could detect changes."

The elder Parr shook his head. "I thought about that, but I feel that the work we're doing should not be left to the chance eye of a camera. The human eye and the human mind is capable of spotting those tiny changes—which may last only a second perhaps. Don't forget that this telescope will take our eye right down almost to the very surface of Mars. It will be like hanging in air only about fifty feet up. We should be able to detect any movement, man-size or greater, but the portion of the surface we can watch at any one instant will be very, very restricted. For that reason human selectivity will be quite important.

"And of course we shall also sweep the wide surfaces with a lower power lens. The job is not so easy as it seems. A needle in a haystack would probably be easier to locate/'

The long vigil began. Gradually the men fell into the routine of their work. As with all things at first, nothing seemed natural, nothing seemed right. On their little barren moon there was nothing like day or night. Only the eternal wheeling of Mars on its own orbit, and the rapid movement of the sun through their black sky. But for them, the sky was forever dark, the stars forever brilliant. The two men on duty would spell each other at the scope, endlessly sweeping the face of their former home. Two would be asleep in bunks. Two would be at work in the ship, or perhaps just wandering the surface of the moon to catch glimpses of other astronomical wonders from beyond.

For besides the eternal globe of Mars, many and varied were the sights they could see from their vantage point. Near as Mars was to the famous asteroid belt, there was not a moment when several of these fragmentary planets were not wheeling across their sky. Some of them came close enough to outshine briefly even the major planets which were the foremost glories of their views.

Mighty Jupiter, ruler of the solar system, was strongly in their view with the naked eye, and four of its satellites, giant worlds for their type, could be seen with ease. Ringed Saturn could be spotted occasionally, its rings detectable. Uranus was spotted amid the cluster of stars, and Nelson Parr had talked over the possibility of locating even distant Neptune by telescope, until Telders worked out its location and showed it to be on the other side of the sun from them, as was Pluto.

But the greatest glory of their sky was a brilliantly shining green crescent that followed the sun in its turns. This world, a glowing, sometimes misty, wonder, was forever accompanied by a tinier white echo of itself, a crescent always similar in shape. The name of this beautiful vision was Earth and toward it their eyes always strayed.

At first, when they had just set up their post, Earth was a thin crescent, large in their heavens. As time passed, as days passed, this crescent grew, became fatter, and as it did so, it grew smaller at the same time. For Earth was traveling away from Mars, swinging away from it and the sun was lighting more and more from their viewpost only as it drew miles and miles away every second.

Nelson Parr and Jim Worden shared a watch together. They drew each other because in the few days they had known each other they had grown to recognize a certain kinship. Jim was older, but, like Nelse, he had been born on Mars and had the old planet in his blood. Fired by the same inspiration to discover the secrets of the lost civilization, Jim had had the opportunity which Nelson had been expecting to have when he had finished his terrestrial training.

Although Jim did not speak of it, Nelson assumed that he had a wife and family among those returned to the green planet. Nelson remembered vaguely seeing a little girl among those in the dome school at Solis whose last name was Worden. But none of the married men of the expedition ever spoke of their families—for they faced a separation of several long and lonely years, and it was best not to allow their thoughts to dwell on this.

There was an odd cross between tension and rest-fulness in their observational work. You couldn't help but feel at ease and at rest outside under the black heavens and the eternal stars. All about, where Nelson would be sitting when on duty, there would be no motion. A plain of eternal silence, of the peace of a dead and sterile chunk of rock. No bird would stir, no mouse crawl, no blade of green, with no breeze to wave it.

Above, only the slowly rotating world of ocher and white and green; to the naked eye forever unchanging save for the slow and ceaseless turning. The stars above were constantly wheeling too. Now and then a tiny planetoid light would move visibly though slowly through the sky.

This was peaceful, the deceptive peace of interplanetary space. Yet, even in this peace, there was unease. Seated as Nelson would be at the scope, protected from the cold and vacuum by a suit which was the masterwork of science, he was subconsciously always aware of the near horizon. Mentally, his brain, conditioned by tens of thousands of years of evolution, kept slipping in a warning that he was dangerously perched at a cliff's edge. And though this was false, for as the young man would walk forward, the horizon would recede and the ground apparently rise and flatten out, still always that falling-away point seemed but a few short strides distant.

That was one kind of tension Nelson felt. The other was the knowledge that their search was important and hard. Upon it might turn the whole future of any colonizing, upon it also might turn the strange and perhaps terrible question as to whether man was alone in his system or whether he shared it with a hidden and cunning foe.

Nelson, his eye pressed to the telescope, his hand to its manual controls, slowly swept the surface of the deserted cities of Mars. His eye moved like an invisible watchman down streets, across empty roads, through untended fields, over the doorways of empty domes. It lingered over the long stretches of viaduct and the lines of green vegetation that revealed the presence of underground ducts and passages right across the vast and arid plains and deserts, deserts that made the Sahara and the Gobi seem small and almost friendly.

He swept the streets of cities that had rarely been visited and never really explored by the always too few colonists. There were differences in cities, for the Martian civilization had not apparently been a static or a barren one. Following the same general lines, forced to do so by the economics of life on an old and drying-up world, there were strong similarities, and yet, where possible, there were variations. Not all houses were domes, though the dome type seemed to be ascendant at the time of the disappearance of life. A few cities featured square or hexagonal structures, some were laid out in patterns that suggested a greater surface life than others, once Nelson thought he even detected traces of whafc^might have been an ancient and abandoned track for a railway structure. He mentioned this to Jim, who took the eyepiece and looked himself.

"Yes," said Worden thoughtfully, "I know that spot. I was there briefly. It's probably one of the oldest cities on Mars, might correspond to an Athens or a Jerusalem in their culture, yet when you are there, it looks as modern as any other. What you can see by eye from the air is often almost invisible or unrecognizable from the ground. Still ... I always intended to go back and spend more time there, for it might have proved profitable. The catacomb structure there is rather more elementary than in most of the cities and might have been the first such, built way back when the Martians first realized their world was drying up. In fact, I remember there were a couple sealed caverns there that our radar screens indicated clearly as museums. Ah, well, we couldn't break in there any more than we succeeded elsewhere!"

Nelson took back the eyepiece and stared again. "Gee, it would be something to find out the history of that city. I wonder if the Martians wouldn't be likely to show up there first?"

He stared steadily at the vacant city, but no motion or change rewarded his eye. Jim said, as he watched, "One thing I'm sure of. The Martians were sentimental about themselves. They had museums, they protected their property and homes, just as the ancient Egyptians did. They may have had a religion that held they would return someday after death, but the trouble with that is that, unlike the Egyptians, they simply wouldn't make any pictures or statues of themselves. Not one!"

"Maybe they had a superstitious idea that if aliens looked on their likeness it would somehow hurt their souls," said Nelson. "Some backward savages on Earth look on photography that way."

"Ahh," murmured Jim, "that would be all very well if the Martians were backward—but they were not!"

Time passed steadily. Even under the strange circumstances routine began to quiet the tension. The Earth was moving ever farther from them, and began to diminish as a brilliant star, to cling closer and closer to the flaming corona of the sun. Drawing ever farther away from Mars, it would soon pass behind the sun, and vanish from the sight of the stranded six for several long months.

As they took their turns at the observation post, they began to expect no changes. They watched but no longer switched back when tricks of their eyes made them imagine a flicker of motion where there had been none. Once McQueen called an alarm, but it turned out that he had seen a brief dust spout occasioned from the bare sand by a rare freak of the red-desert winds.

The seasons of Mars were changing steadily, and Nelson watched the gleaming white polar cap dwindle and the southern polar cap build up. The Earth clung so close to the sun that it could be glimpsed only by straining against the sun's fiery glare, and at last came the moment when the tiny green dot vanished completely from their sky. This was a somber moment for the expedition. For a brief spell they went around silent and thoughtful, feeling more than ever how thoroughly they were cut off from their parent world and all they held dear.

But the observations never ceased. Always two men were out watching, checking, measuring. Jim and Nelse were on duty during a period when Mars was but a quarter crescent with night creeping steadily across its face. On the edge of the daylight portion, the city which Jim had called one of the oldest was in view, and Nelson concentrated his scope upon it. Several times he had returned to this Martian Athens, his mind speculating on the mystery of a history no man might ever learn. His eye moved over its hexagonal buildings, as the shadows of twilight lengthened steadily. He stared down at the circular doorways set in the homes. He looked at the square flat plates in the ground that opened into underground passages and chambers unseen by man. He could almost see the plants closing in on themselves, folding their leaves into furry fists against the oncoming cold thin-aired night.

Slowly the vision in his eyepiece grew darker as night swept over the city. In a few more minutes he would have to shift his view elsewhere, for the city at night became invisible in the darker dark of the Martian night. Still buried in his thoughts, he stared down at the city, his eyes straining to keep the details of houses and markings as the view changed from light to dark, turned gray, became blue-gray, then blacker and finally merged into black. At the very instant that he stared, he saw a flicker.

around the scope while Nelson was explaining again what he had seen. There were excited comments and suggestions, then John Carson Parr called for silence.

"Now listen, men, let's not lose our heads. We're not likely to spot any more signs immediately and certainly not while that area is in darkness. We know where to look and from now on, we'll keep a strict watch there every minute it's in the sunlight. Go on back to your duties. I think we've finally found our quarry, but this is only the beginning."

Reluctantly the four off duty drifted back to the ship. Jim and Nelson stood out the rest of their watch, but they saw nothing further to excite comment.

In spite of their efforts, it was not until four watches later that something was seen. This time, again in the same ancient Martian city, one of the men was sure that he had seen a crushed spot in the growths around a certain structure that looked as if some large craft had landed and departed from there. But keeping track of one certain spot is hard to do when the surface is constantly turning and your own observation platform, the little moon, is also moving.

Next thing was the discovery by Gutman of a door in another part of the city that was unquestionably half open. They could see no sign of action near it, but there it was, not closed. By the time the next observation of the city occurred, about twenty hours later, that door was shut again.

The six watchers were keyed up with excitement. Among themselves they were discussing who would be the lucky man to first spot the Martians. "It's pretty obvious," said Gutman, expressing the general opinion,

"that they waited until Earth was entirely out of the sky to come out of their hiding places."

John Parr was not certain, however, that they would ever be able to actually make out the forms of the Martians if they did spot them. "We're still a little far away to see any definite shapes of creatures. If you saw a man from where we are, you would not see more than a blurry spot. We may have actually to make a trip down to Mars and sneak up on them."

Jim Worden laughed. "A fine chance we'd havel These Martians are the cagiest creatures anyone ever hunted. I'll bet they've got some sort of radar system that would tell them instantly the first time we even hit their atmosphere. Don't forget how long they successfully hid from us."

A strange idea suddenly slipped into Nelson's head. He debated with himself whether he should mention it, finally chancing it. "Do you suppose that perhaps these are not the Martians? Maybe they're some other set of explorers from elsewhere in space taking a look around now that we've abandoned the place?"

Jim Worden laughed. Bryan McQueen patted Nelse on the back. "It could be, but it's highly unlikely. After all, how would these other explorers know we'd left unless they'd been watching us all along? Now the Martians might have been watching us, that I can believe. But why look for trouble elsewhere? One set of extra-Terrestrials is enough."

By the next period when their Martian Athens came into sight, it was early morning there on Mars. As the sun rose and its belt of light flooded into the streets of the ancient town, McQueen, who was on observation, let out a shout. Piled in plain sight in the area between two structures were several large objects exactly like boxes or crates. They all took turns looking but there was no doubt about it. They could see no motion around, but it was clear that now the unknowns had decided they could dispense with a certain amount of secrecy.

"How many more hours of observation do we have?*' asked the elder Parr anxiously.

Telders glanced up, gave a quick calculation. "Not good. This sector isn't going to be visible from here for more than another couple hours. Then it will be rotated away from us and we won't see the city for— ummm—maybe thirty hours."

John Parr slammed one gloved hand angrily into the other. "Blast!" he groaned. "This is just the time we have to keep that place under constant watch. I'm sure, I'm as sure as I'm standing here, that something or someone is going to pick up those crates and take them somewhere. If we could only see how and who and where they take them to, we'll be well on our way to solving this whole business."

"There's no way we can watch that city all day," said Worden. "Not from here."

"Then why can't we find a better spot where we can see it?" urged Nelson. "Could we see the city all day from Deimos?"

"Now that's an idea!" said his father quickly. "Telders, will you check that and see?"

Telders ran inside their cruiser and, after a few moments' checking on their charts and calculators, called out on his helmet phone. "Yes, if we can get an observer on Deimos within the next two hours, we could watch that city from there during the broad daylight for at least the next ten hours."

John Parr called back to Telders, "Is the ship's lifeboat in workable order?"

"Of course," came back the instant reply. "And it can make the trip easily."

"O.K.," said Parr, "we'll do it." He turned to the men. "Worden, you and Nelse were due to take the next shift, so you'll be in best shape for the job. Take the lifeboat, load on the other scope and lenses, and get going. Telders will give you the figures for the trip."

Nelson's heart gave a bound. Then he and Jim Worden raced back to the big cruiser, followed instructions, hastily loading the necessary equipment in the cruiser's small lifeboat, itself a tiny spaceship capable of interplanetary flight on its own. There was no need to load up on food or water. The little craft always carried sufficient provisions in the event of an emergency and had its own water flask and regeneration system. When the two had the lenses and frame of their scope stowed safely into the tiny cramped cabin, they opened the emergency panel in the cruiser's side and the little craft slipped out gently and bounced onto its own runners on the rocky surface of Phobos.

Telders rushed out of the navigational corner of the bigger ship, handed them a sheet of paper. "Here's the data on our various satellite speeds and positions. Mostly you can make the trip by eye, however. It's only a short distance as they gol Take it easy when you come into Deimos though."

Worden and Nelson checked their own suits, hastily went over the lifeboat's equipment as every good spaceman should and verified with their own eyes that it was all in working order. The little ship was only about fourteen feet long and its strong little engine and fuel space occupied fully half of that length. The two would have to cramp themselves into the forward seven feet along with their belongings.

"Who's going to drive?" asked Jim. "I know how, but it's been quite a number of years since I piloted anything in space. Zipping through the air in explorer ramblers is about my pace today."

"I'll take it up," said Nelson, sounding more confident than he felt. "I handled these at the Space Academy only a few months ago and I'm fairly sure this will be no different."

His father nodded. "O.K., it's probably better that way. The younger you are, the better your reactions and the faster your control. Just remember to keep your head and you'll be all right."

So Nelson slipped into the driver's seat and Jim piled into the space next to him, almost on his lap. They slid the transparent quarter-top closed over them, set the molecular seals. Jim spread out Telders' notes on his lap, where he could call them off if needed to his companion.

Nelson opened the throttle, felt the engine hum. He kicked the ground rockets into operation, felt the ship slide forward on its runners over the rocky plain. Boosting it quickly, he blasted his jump-off tubes and with a sharp jolt they were off the surface of Phobos and into space.

"Watch that!" yelped Jim. "I almost banged my head on the top with that jackrabbit takeoff!"

"Sorry," Nelse murmured, busy at his controls. "I'll get the feel of this in a moment. I forgot that we weren't taking off against Earth's gravity."

He set his teeth and flexed his fingers again. This was a test he had never really had. It was one thing to pilot this type of craft under Earth conditions in controlled testing spheres, quite another to be entrusted with it in real earnest under real space circumstances. He eased up his speed, took the little craft easily around in a wide half circle and headed it outward from the little moon.

They could see their objective ahead of them, a tiny spot of white moving across the endless panorama of outer space. Mars' second moon was half the size of Phobos, being only about five miles in diameter. It was nine thousand miles farther away from the red planet than the inner moon and took nearly three times as long to circle it once. As such it was even now moving slowly over the daylight hemisphere, and their mystery city objective would be in plain sight as Deimos moved through the Martian sky.

Nelson Parr's problem was simply to pilot the little boat outward and into the orbit of Deimos, bringing it into the same speed and cutting ahead of it as he did, so as to arrive at the little satellite at a proper landing tempo. He set up the various figures on the ship's little automatic navigator and after it had clicked and chewed this data electronically he noted the times and alternate speeds with which he was presented. He chose the alternate that would get him there fastest, although this was always a riskier course.

He stepped up his rocket blasts and the two men felt themselves being pushed back in their seats as the little boat accelerated steadily. Nelson was determined to make the astronomically short trip in less than two hours. He piled on speed and boosted the craft up heavily, then let it coast for about half an hour at over twenty thousand miles an hour top speed. While they coasted, Jim and he speculated on the Martians.

Nelson mentioned again the strange three-fingered handprint that he had found on the Congreve.

Worden remarked, "I'm inclined to think now that these creatures were not the Martians. Your suggestion before sounds a little more likely now."

"Why do you say that?" asked Nelson, his eyes watching the steadily growing disk of Deimos, outlined against the star-strewn black of space.

"Because I've figured out that the Martians must have had much the same kind of hand we have. I've studied their things, their machinery, their household stuff. It has always seemed to me that their handles and controls were designed to fit a hand like our own and not anything very different. Of course, I could be mistaken, but in things like this, the mechanics of everyday living can be a pretty reliable guide."

Nelson nodded briefly, switched on the engines and began his braking maneuvers. Again they were shoved into their seats, and conversation died as they fought to bring the craft into landing adjustment.

Nelson was too busy at the controls to pay much attention to outside things, but Jim Worden was watching space. He was staring at a group of bright stars when suddenly one of them blinked out. He stared wide-eyed, then another next to it blinked off and the first came into sight. "Hey!" he said. Nelson looked up. "What?"

Worden stared sharply. He could see nothing more. "Sorry, thought I saw something just then." He explained what he'd seen. "Thought maybe it could have been another ship between us and that sector of the sky."

"Probably just a meteor," said Nelson.

Now they were rapidly approaching Deimos. The little moon, like its sister, was quite spherical and fairly smooth-surfaced. They winged around it a couple of times to brake their speed exactly, and then Nelson brought the ship down and skimmed the surface. It was apparent that Deimos also showed but one hemisphere to Mars; a curious circumstance was Nelson s fleeting thought, as he jockeyed to find a good spot for their observations.

Finally, he came down for his landing on a wide flat belt, shining ruddy in the daytime glow of Mars. They slid neatly to a perfect stop on a hard and smooth surface.

"Good work," said Jim glancing at the control dials. "Telders couldn't have done it better. Now let's get the junk out."

Adjusting their suits to space, they slid open the boat's top and climbed carefully out. Outside of the fact that the horizon was even nearer their feet than before, this little world was not very different from the barren satellite they had left. Above them the globe of the red planet was visibly smaller but still quite large enough to see details with the naked eye.

Without wasting words, they unstrapped the framework of their telescope. Then they looked around. "This isn't as good a landing place as we thought," said Nelson, now that he could see his whereabouts better. "You might have told me I was coming in on a slant."

"Didn't want to upset you," said Jim. "Fact is I was hoping I wouldn't get another jolt."

Mars was not properly in the center of their sky, but down at one side. "I think we'll just carry the frame and lens over about three miles and we'll get a better view," said Nelson. Suiting action to words, he hefted the framework and apparatus, and Worden loaded himself with other stuff. Then they started off in easy long bounds.

In only a short time they had covered the space, so easy is it to travel without weight. The boat had fallen out of sight beneath the horizon after the first two or three such bounds. Almost a fifth of the satellite away, on the flattish plain, they set up their instruments.

It was more than two hours since they had left Phobos and they were relieved when they finally put their eyes in turn to the eyepiece of their scope to see that the mysterious crates were still standing in plain sight exactly as they had been. By this time their friends on Phobos had lost sight of the objective. It was a relief to know that in the half hour that no one had been able to observe the spot, nothing had happened.

There was one drawback though. At this distance from Mars, the lens which had been powerful enough to carry their vision to such a close range was weaker. Visually they seemed farther away and streets and objects in the ancient Martian city were therefore smaller in appearance.

"Is this the strongest lens we have?" asked Nelson, bent over the instrument.

"No," said Jim. "There's one stronger still."

"Got it here?" asked Nelson, still absorbed in the view.

"No, it's back on the ship, I'm afraid," said Jim, after looking through the stuff they had brought.

"Maybe one of us had better go back and get it," Nelse suggested. "If we spot anything, we're not going to get any decent details with this eyepiece."

"I'll go," said Jim. "You keep the watch." He set off back to the ship without waiting for Nelson to object. In a few moments he had disappeared below the narrow horizon.

Nelson Parr watched the pile of crates, but nothing happened. He casually swept the telescope back and forth over the city, checking its open areas and connecting viaducts. Then he drew in his breath sharply, stopped his sweep. Over a hitherto unnoticed old road, by tie side of the green belt leading into the city, three shapes were moving!

He watched them and was able to make out that they were vehicles of some sort, rather tear-shaped and moving swiftly without sign of wheels. If he had the stronger lens he could have made out their full detail, but as it was he could make out their dull metallic glint and nothing more.

He fidgeted, wondering when Worden was coming back. He kept the teardrop shapes in sight, noticing that they were following a route that would bring them up to the crates fairly soon. Undoubtedly they were conveyances which would pick up the boxes and take them somewhere else, probably to the main hideaway of the Martians. He dared not take his eye off them and yet he longed to drop everything and go after Worden to hurry him up.

It seemed to him that Jim was taking unusually long. He couldn't call him on his helmet phone, for he knew that the limited direct beam transmission would work only when both senders were in sight, or at least on the same plane.

Quickly he calculated mentally the speed of the teardrops and the distance and time it would take them to reach the crates. That should give him about twenty minutes. He decided to take the chance. He removed his eye from the view, glanced around. Worden was still not in sight.

He turned back to where they had left the ship and went after it as fast as he dared in the nearly gravity-less conditions of little Deimos. Leaping along he kept watching to spot Jim returning to him, but strangely he did not see him.

Before long he spotted their spaceboat in the distance. He made it in three more giant leaps—and found Worden. His friend and companion was lying just outside the little rocket boat, lying flat on the ground, motionless.

Nelson bent over him, turned him over. Jim Worden's helmet was shattered, his air gone. One look

It wasn't much. He and Jim hadn't expected to stay on the smaller moon more than a dozen hours or so, hence very little food, scarcely more air. It was clear that Nelson's own hours were seriously limited. He glanced at the radio in the ship, but that too had been ripped apart. He could not even call for help, though his chances of being heard even if it were working would have been slight.

He searched for a weapon, wondering whether the ship had carried any among its regular lifeboat provisions. But there were no weapons, for what need would an interplanetary lifeboat have for such things in the lifeless reaches of space?

So he turned back to the ship, standing before the crumpled body, and knew he was alone, unarmed on a moon stalked by the unknown. He realized that he himself must be their next target, that they must have him marked for death.

Warily he glanced around. Low ridges of rocks bordered one side, on the other the horizon cut the plain very near to him. All a foe would have to do would be to stay just beyond the horizon, stalk, and when his back was turned long enough, a few flying leaps would be enough for the foe to land on his back. Who could tell who was waiting just out of sight?

Nelson thought fast and coldly. He might die, but he would see his slayers first. He would not be caught. He would come to grips with them and they would see, yes, they would see.

And then another thought struck him. He remembered Jim's remark during their trip to Deimos about another ship, something that had blocked the light of stars for a moment. That, he thought, must have been the spaceship in which these unseen stalkers had arrived. That ship must still be here, must be somewhere on DeimosI

The thing he could do, the only apparent course that held even a glimmer of a chance for him, was to try to find that other spacecraft, find it and somehow capture it! Wild as that chance seemed, there was simply no other course! And while hunting it, escape the clutches of the killers!

Nelson looked around sharply. He saw nothing, yet instinctively felt that he was being watched. Behind the rocks possibly. ... He turned, glanced into the spaceship, acting as if he suspected nothing. Then slowly he walked around the ship. On the other side, he ducked down as if to examine something, glanced carefully around the side, hoping to detect some signs of his hunters. But they were out of sight.

He walked back, then started off in bounds back to where the telescope still stood. He would act as if he did not know they were following him, but he would keep moving fast enough to prevent their leaping upon him unawares.

He retraced his course to the observation post in great leaps, feeling they must be following him. Once, glancing back at the top of a particularly high leap, he thought he spotted a movement in the distance. But he could not be sure. Leap, bound, leap, he went on, the great ruddy disk of Mars looming higher in his sky, until at last he came to the spot where he had left his telescope.

It was not there! It was gone! Nothing was present but some tracks in the dust, some blurry footprints, prints of which all that could be told was that they were not his own.

Nelson wasted no time searching around. It was clear to him that there must be several in the party of unknown stalkers. While a couple were watching the spaceship, others must have carted away his instruments, probably taking them to their own spaceship.

Nelson spotted another bit of motion on his horizon. Wheeling around, he felt he saw something else move behind one of the rock ridges which seemed to be about the only distinguishing feature of this otherwise bald-surfaced worldlet. They were closing in on him from several sides.

He leaped again, continuing in the direction in which he was going. Now he cast caution to the winds, and leaped as fast and far as he could, determined to see if he could outdistance his pursuers and thus lose them, or perhaps accidentally arrive at the spot where their spaceship was resting before they had time to get there and move it.

What followed now was like a scene out of a peculiarly unpleasant nightmare. Nelson was moving forward over the bleak red-lit landscape of Dehnos, hurtling now upward into the black and starry sky, now plunging with eerie slowness down toward the gray rocky landscape with its fiery overtones and jet-black shadows. Forward and forward as if forever, and as he moved, Mars seemed to move in the sky, for he was on his way to circling the tiny world and nearing the hemisphere where Mars never shone, the side upon which the sun was now shining equally strangely in the dark cold sky.

Behind him he occasionally glimpsed movement, a tiny spot, glinting red as the Marslight hit it at the top of its own pursuing bounds. He urged his body forward and drove on, silently, in the murderous emptiness of Deimos.

After a while Mars vanished from view entirely, and below him the moonscape shone cold and white where the far sun with its weirdly flickering corona dominated the heavens. And now he came to a very rough section of the surface, where the flat plain was for once replaced with a frothy sea of ridges and crevices. Here there was the darkness of space on the surface, here there were shadows and hiding places.

He bounded into a lightless tiny canyon and here decided to end his flight. He had seen no sign of the other spacecraft, but it occurred to him now that this very area might be the ideal place to hide it. He slipped into a dark and shadowed corner beneath an overhanging wall, where no light penetrated to reveal his presence and there he waited.

At first there was no sign of pursuit. He caught his breath again, stood there tensely waiting. Then he saw a spot flicker past overhead, lit by the sun a moment, a spot that could be the size of a bounding manlike being. Another followed and then three more in rapid succession.

He waited, planning to slip up above the ridge and spy on them, but suddenly one of them shot back overhead. Quickly Nelson crouched down in the shadow. Had they spotted him?

One by one the mysterious figures shot back, and it dawned on Nelson that they too had landed in this same nest of ridges and canyons. Then perhaps his guess about the hiding place of their spaceship was right? Was it somewhere nearby?

He felt a vibration in the rocky surface through the metal soles of his boots. The pursuers were in this very canyon walking, walking toward him!

Nelson Parr started to walk forward, keeping ahead of the unknowns. If they were coming his way it meant one of two things. Either they had spotted him by some means, such as radar, or else this was the canyon leading to their spaceship. In either case, the trail was hot and Nelson might come upon the ship before they did.

He tried to keep his steps from vibrating. It came to him that apparently they had not spotted him after all, had abandoned the chase, for the heaviness of their tread indicated they were not concerned with the possibility of warning their quarry. Therefore it must be they were heading toward their ship.

Nelson kept in tie shadow and moved silently along, turning a sharp corner. He stopped, baffled. For beyond the corner there was only the sudden wall of the canyon, the end of the crevice—and no craft. Behind him the tread could be felt, echoing through the stone with that long-carrying intensity possible only in the cold and vacuum of a little world. Desperately his eyes searched the canyon and now he saw that in the base of the wall was a deeper blackness, a black spot that the reflected light did not penetrate. It was a cave.

Quickly he dashed across the remaining space and into the dark opening. He found the cave to be a natural tunnel, a crack penetrating downward into the rocky surface of Deimos. He hid in the entrance, waited.

In a few moments, five figures rounded the corner of the deep canyon. They were manlike, walking upright on legs, having arms like men, muffled from all detail by curious gray rubbery garments from head to toe, with only dark slits for eyepieces. Two of them carried the frame and equipment of his telescope, the others carried objects that might be weapons. They walked on, directly toward Nelson, directly to the mouth of his tunnel.

Nelson had no choice but to push farther on into the blackness. He scrambled ahead, hoping there were no sudden drops in the lightless dark interior. He bumped into a wall and, with his pursuers not yet quite at the opening, dared to flick on a light momentarily from his helmet. He saw that the tunnel turned and proceeded in a steadily downward incline. He headed on, disappearing from view as fights suddenly flicked on where he had been as the five unknowns walked into the tunnel.

Casting caution aside, Nelson ran as fast as he could down the dark tunnel, in the uncanny blackness. As he ran he gradually became aware that there was a dim bluish light in the depths of the tunnel, that some sort of radiation or glow made the tunnel not as pitch-dark as it had been at first. And in this dim glow he also became aware of something else. This tunnel was no natural feature. It was smooth-surfaced, leveled, graded. It was artificial. And just as this became clear to him, he burst into a crossing where the tunnel branched into three short corridors, each of which ended at a closed metal door.

He hesitated, not knowing which way to turn. Knowing his pursuers were close on his heels, he went to the door directly before him. He saw no knob or obvious means of opening it. He pushed upon it, but it remained immovable. Feeling the vibration of footsteps, he glanced rapidly about, picked the farther corridor, ran to it, and flattened himself against the wall, hoping to keep himself out of sight, hoping that he had not picked the very corridor his pursuers would take.

He waited, breathless, and then the five came into sight and marched up to the middle door, the one Nelson had tried. Without even glancing around, the first man reached up and probed a hole set just to one side of the door and shoved a finger into it. The door slid aside and the men marched through and it closed behind them.

Nelson waited a moment, then slipped out and went softly up to the door himself. He glanced at it, spotted the little indentation which evidently was the electronic control that motivated it.

For a brief while, he hesitated. It was obvious to him that this was no hiding place of a spaceship. That even if the five unknowns had arrived on Deimos by a ship, that this must be much more than that. This looked like a permanent hideaway, and not the hangar of a craft. He did not have to follow them. He could go outside now and hunt for the real spaceship hangar. But he knew that would be possibly pointless and might simply make him a target for some other sentinel's chase. No, the thing to do was to get to the heart of the matter,

the entry room was an airlock, that he had entered a place beneath the surface of the little moon where there was air under pressure. But where—and who would be watching?

He flicked his helmet light on again. This time he saw that he was facing a short corridor from which branched off a number of others. He stepped through the door, and as he did so, the door slid silently shut behind him. In the darkness he strained his eyes, but the five strangers who had preceded him were out of sight. He saw no sign of life.

He dared his helmet light again and this time left it on, dimly glowing, just enough to betray the outlines of his immediate surroundings, not enough to attract attention.

How was he to know where to go, which corridor to follow? He tried to recall whether he had ever read anything of the system of the Martian underground corridors that would help him. Explorers had worked out what they believed to be the methods and general layout of the subsurface workings of Mars. If these unknowns were the lost Martians, then perhaps that system would work here.

But he could think of nothing that would help. And it also occurred to him, grimly, that it made no difference. Anywhere he went here would be a discovery, any path might lead to disaster or to hope, and only trial would tell. And so he stepped out softly and made his way along the corridor directly ahead.

It seemed to wind in a generally curving way and it seemed to descend farther and farther beneath the surface. At last he rounded a corner and in the light of his helmet he saw that there were several doors set into the wall along this section. He stopped before the first, saw that the indentation system was standard here. He reached a finger for it, hesitated. It dawned on him that nowhere on Mars had he ever recalled hearing of or seeing such a system. The Martian doors were always circular, opening when they did by a touch.

Could it be that these moon-hiding strangers were not the lost Martians? He remembered Jim Worden's speculation on the hands of the vanished civilization's makers and the contrast with the handprint on the Congreve. He opened the door.

There was darkness, and his helmet light penetrated it to show that it was but a room, moderately sized, and empty. He glanced around, but there was nothing there and dust lay undisturbed on the floor.

He withdrew his head, went on to the next door and tried that. Again an empty room. One after another he tried the doors in this section and they were all bare. Evidently this part of the hideaway had never been occupied or else had been abandoned.

He went on along the main corridor, around more turns, winding down again and coming out on a new level. Here there were more rooms. He wondered if he were right to pry into them, for he might suddenly burst into one which was occupied. But again he realized there was little else he could do.

He punched open the first of these new doors, and this room was not empty. No one was there and it also was dusty, but it was obviously a storeroom of sorts. There were strange balls there, big metallic globes as large as Nelson himself, with curious markings, and bands of some substance to hold them together. Possibly boxes or containers of some sort . . .

The next room held an assortment of globes of smaller sizes, one of which was half open. Nelson went into the room and glanced into the sphere. It was almost empty, but there were scraps of stuff inside, the sort of material that might be used in packing delicate apparatus.

Then these were indeed storerooms. Nelson wondered if he would be able to find one with weapons in it or something practical. It dawned on him that he was hungry and thirsty. He hadn't eaten in quite a long time. Perhaps if he hunted hard enough he might find food.

He went into every room along the line then. Most had the globes, one was piled high with huge rolls of some plasticlike substance, another had shelves with stocks of little objects tooled from metal, the use of which he could not guess. And finally he came to the chamber at the end of this particular line and found what he sought.

This room had shelves piled high with curious cubical packages, soft to the touch, strangely like packets of raw tea. He lifted one, then broke it open with his hands. He saw that inside it was of a spongy grayish consistency and looked as if it might be some sort of food. The only way to find out would be to test it.

He had not opened his helmet thus far and now he had to face that decision. He couldn't eat with his helmet on; there was no device that would permit that. And though there was air here, he had no idea as to whether it would prove breathable to him. It might be very thin, it might be an atmosphere designed to give comfort to beings that would die in oxygen. If, for instance, the unknowns had originated on a planet like Jupiter or Saturn or Uranus, this air would be high in chlorine and ammonia, and would be deadly gas to a human.

But on the other hand, what choice did he really have? So he reached up and opened his helmet. There was a puff as the air in his suit escaped into the quite thinner air around. He choked for a minute trying to catch his breath, coughed severely several times and then managed to control his lungs. The new air was breathable. Thin, stale-tasting, oddly metallic, but breathable.

Nelson sat down on the floor and looked and sniffed again at the broken packet he held. It smelled moldy, but definitely like something of an organic nature. He tasted a bit of it experimentally. Not at all bad, he realized, for it tasted a bit like mushroom. He crammed a chunk into his mouth and munched on it.

It proved quite satisfying. Not quite like anything he remembered having eaten, the nearest he could determine of its taste was as if you could imagine bread made from mushrooms gone a little bit sour. He supposed that if he were not so hungry and the surroundings not so strange he would refuse to eat the stuff.

He sat there satisfying his hunger and wondering where he could find something to drink when he felt the vibration of footsteps coming from outside. Instantly he snapped off his helmet light and sat rigidly in the darkness, wishing he had thought to close the room's door.

The footsteps came closer, stopped nearby. For a few moments there was no sound, then suddenly the room was flooded with light. Nelson was blinded as the glare hit his eyes. He leaped to his feet.

"Stop! Stand right where you are!" said a sharp high-pitched voice. Nelson stood where he was, staring at the man standing in the doorway, the being from the interior of Deimos.

He was a human, or at least human enough to pass for such on first inspection. He stood about five feet high and his odd hands were holding a curious pistollike weapon, holding it a bit tremblingly but managing to keep it pointed at Nelson enough for the young man to know that to move would be to invite sudden death.

The stranger's skin was pale and white like that of a being who has spent all his life indoors, away from the sun. There seemed to be a faint bluish tinge to his skin. His eyes were sharp and hazel-colored, almost yellowish. His hair was white with a glint of metallic silver, sparse on his scalp but adorning his face in a short straggly beard. The old man, for he was visibly old, as shown by the lines around his eyes and face, was clad in a tight-fitting one-piece blue garment without ornament or distinction of cut.

His hands had but three fingers, and they ended in a short splay of tiny tendrils instead of nails. They were the hands of the unknown searcher of the Congreve.

Nelson stood, arms away from his sides, staring at him, mentally wondering whether he could chance an attack. The old man was scared, and a scared man with a gun can be many times more dangerous than a calm one. Nelson decided to wait and see what the old man had to say.

"Sit down and finish eating," said the old man in a whispering voice. "Sit down but don't make any outcry; don't make noise if you want to keep your life."

Nelson was still hungry and he saw no reason for disobeying this order. Something was wrong here, he told himself. This man did not act like an aroused conqueror or proud captor. Casually the Earthling squatted again and finished the piece of the synthetic bread-food he had been chewing on when discovered.

The old man stood there waiting for him to finish. When Nelson had swallowed the last piece and looked up at him inquiringly, he nodded to himself and said, "I don't want to harm you, so please just listen to me. I can help you a little, if you will do me an assistance."

"Can you lead me to Jim Worden's killers?" Nelson said. "That's who I came in here to find."

"Who is Jim Worden?" the stranger asked, puzzled.

"Jim was my friend," Nelson said slowly. "He was struck from behind, his helmet shattered when your men wrecked our craft up on the surface."

The old man seemed really startled at this, his hand shook visibly. "Killed? They really killed a manl Oh . . , this is very bad!" He repeated this to himself a few times, then suddenly paled and said very quickly, "Oh, you must not think I did it! Not me. Not my friends. I wouldn't do such a thing, never."

"If you didn't do it, who did? How can I find them and how can I get out of here afterward?" Nelson felt himself getting the uppermost for a moment as the old man showed genuine panic at the news of the slaying.

But the stranger recovered suddenly and his eyes narrowed. "Oh no, you can never get out of here. You must never leave here. Your friends on Earth must never know."

Nelson sat back on his heels. "Oh? Well, then what's your game?"

The old man paused a moment. "You don't understand. But I want to make a bargain with you. I can't let you go home, but I can lead you to the ones you seek if you will agree to help me also."

Nelson thought a moment. Whatever could this stranger want? He decided to pretend agreement. After all, the more he knew, the more chance he had of escaping. He nodded. "O.K. What's the problem?"

Now the old man seemed, to be the uncertain one. It was as if, having gone this far, he had exhausted his limited stock of courage and didn't know whether he could proceed. Finally he started to explain:

"My name is Kunosh. I am ... ah ... an official of . . . my people here in Deimos. Sort of like a . . . chairman or maybe a sheriff ... or something like both, I can't quite explain here. We are a small group of people and we live here in the interior of this little moon. I can't tell you how we came here because I am not allowed to and we don't have time for it. You must take my word for it. There are several thousands of us living here."

The old man stopped, groping for words. He twisted the weapon in his hands, forgetting entirely about keeping it pointed at Nelson. But the young man realized he had more to gain by listening now than by attempting to wrest it from him. Kunosh went on again:

"You must understand, young Earthling, that we don't bear anyone any ill will. We never harmed a soul, we never want to hurt anybody. I must tell you so that you will know this, I must tell you again we are opposed to the use of force. We never want to fight anyone, we never want to hurt anyone. Certainly we cannot stand to kill anyone. None of us hurt your friend. We couldn't, we just simply couldn't, couldn't! It's what we believe, it's what we feel!"

Nelson looked at the weapon in Kunosh's hands. He thought to himself that not so long ago Kunosh was apparently willing to use it on him. The old man seemed to read his thoughts.

"My threatening you with this . . . ers-gun . . . was the most dreadful thing I ever had to do in my life, believe me. I think I would have died if you had made me shoot it!

"But now that you are listening to me, you must listen more. There are a few bad men among our people who have lost faith. They have slipped from the strict tenets of their ancestors and they will use force! From what you told me, they have already done so. They have become dangerous to us, to you. In our eyes they are turned monsters, degenerates!"

The old man stopped, overcome by the horror of

Now the lighting in the corridors was becoming brighter and the air seemed fresher. Nelson felt a breeze against his face, a breeze that came and went and he realized that an artificial air-circulation system . was in operation near the central depths of Deimos. The floors were no longer dusty and began to show the marks of feet and usage. Then at last they rounded a turn and came face to face with a group of people walking.

The strangers' faces showed recognition and unconcern when they saw Kunosh, who was ahead, but as soon as they set eyes on Nelson Parr there was visible consternation. They shrank against the walls to let him pass with the widest of margins, their faces went pale, and they showed every sign of outright terror.

The people were of the same race as Kunosh and all were clad in very much the same sort of undistinc-tive garments. The women among them were distinguished only by a slightly smaller size, a delicate cast of features and somewhat more ornate clothing, generally of a lighter shade of blue, or in several cases even green. Nelson supposed that perhaps these differences indicated marital status or perhaps work relationships.

Now there were doors that were open and sometimes even open underground plazas. Nelson could see that they were passing through a busy community. He saw workshops where oddly shaped machinery worked unattended at unguessable tasks. He looked into doorways that led into homes, where two or three pale-faced and fragile children would look soberly at him and shrink back out of sight. He passed people carrying packages, women carrying babies. He saw open chambers at junctions in the network of tunneling where markets seemed to be in progress, and once they walked through a series of rooms wherein strange green-gray plants were growing under the glare of sun-type lamps. This was obviously one of their chemically operated farms, such as would have been necessary to sustain life in such a sunless world.

But wherever Kunosh and Nelson put in their appearance, there were fright and terror. On Earth, Nelson thought, if strangers appeared in some remote region of the world, they would be surrounded by inquiring, curious grownups and screaming, excited children. But these people were lacking in all that. They seemed terrified of anything strange, they seemed —he groped in his mind for the picture he sought— they seemed like rabbits or even pale frightened white mice.

None of the men questioned Kunosh, though plainly he was recognized by all. Whenever he and Nelson put in an appearance, there was silence and a scurrying away of all who dared flee.

Nelson was aware that they were nearing the heart of the little world. At last Kunosh stopped before a door, opened it, and they slipped into a narrow dark hall. Kunosh closed the door and they stood again in darkness.

"Be careful now," the old man whispered. "We are right next door to the Central Control Hall, where . . . the monsters . . . are holding our leaders prisoners. This is the heart and brain of our world. This little hallway runs right next to it and I can lead you to an entrance that will take you right near these . . . usurpers. Follow me quietly."

He started off in the narrow darkness and Nelson followed at his heels, holding the ers-gun and wondering desperately just what course he would follow. Now that he was close to the end of his mission, he became sharply aware of how little he knew, how little Kunosh had actually told him.

For instance, how many of the enemy were there? Were they armed? How would he know them when he saw them? And a last thought suddenly popped into his head—exactly what would the ers-gun do? Did it shoot a pellet as a pistol would? Was it a ray projector of some sort and if so, what sort of ray? Would things explode? If it was atomic in nature, it would be extremely dangerous to fire it in a closed room . . . deadly as well to the one who fired as to the one who got shot.

It occurred to him then that perhaps Kunosh knew that, knew the shooter would die also, and that accounted for his own reluctance to handle the gun. Nelson might thus be a convenient guinea pig. On the other hand, the obvious rabbit-nature of the people and Kunosh's fanaticism argued against that theory.

Nelson's gloved hand felt sweaty as he held the strange weapon. He knew he would have to make up his mind in a matter of split seconds if he had to fire it. He didn't know what he would do.

Kunosh came to a stop, and Nelson crowded up close to him. The Deimosian whispered, "I'm going to open the door now. You rush in. The fiends—the fiends wear stripes!"

Suddenly there was a crack of dull light which widened as a door silently rolled back into the wall. The room into which Nelson looked was dimly lit, long but narrow. There were various desks and platforms up and down its length. It looked like a combination business office, spaceship control room, and electronic communications relay station. There was a small group of men, perhaps a dozen in all, standing around a lighted panel in the wall opposite Nelson, apparently discussing the glowing sets of hieroglyphics and Deimos language notations showing there.

It was a marvelous stroke of luck that none of the men were looking their way. Nelson stepped softly inside the chamber. Now he saw that among the dozen figures were five wearing garments which were striped red and black up and down from neck to ankle. These, then, were enemy.

Nelson looked down at the weapon in his hand, estimating whether he should chance using it. He raised it but then was startled to realize that it had no indication of any directional finder. Its operating end seemed glassy and wide and there was no way of telling whether it would spray all in sight or only one small spot.

He could not aim it at any individual without taking the chance of hitting all. But the weapon seemed heavy and strong. He reversed it and, walking softly and swiftly up to the group, swung it back over his head and brought the heavy butt end down on the skull of the nearest striped man.

The man fell as if struck by lightning. The others turned with cries of consternation and fright.

Now suddenly feeling the flush of anger and remembering the vicious way Jim Worden had been killed, Nelson whirled upon the other four foemen.

There were screams of terror from everyone in the room. The blue-clad Deimosians dashed around in sheer panic. The red-and-black characters seemed equally alarmed, and in their confusion Nelson was able to knock down a second with a swing of his gun.

Then the other three launched themselves at him. He felt a fist crash against his face and was surprised to find it so light. Nelson waded into the three, realizing how big and strong he was in comparison. He grabbed two, disregarding their blows and banged their heads together. The third broke and tried to run.

"Stop him!" called Nelson, but not one of the blue-clad men moved. They were simply standing away from him, shaking, and white with terror. The man in the striped suit was nearing the farther door, clearly going to make a get-away, when the Earthling swung the ers-gun and threw it with all his might, just as he had learned to do when playing football at the Institute back on Earth.

His practice stood him well. The bulky weapon shot through the air and crashed against the running man. The enemy fell to the floor and lay there stunned.

Now Kunosh took charge. He called out orders to the Deimosians in the room, and they threw off some of their fright and hastily tied their recent conquerors hand and foot.

Nelson looked around. That was fast, he told himself. "Are there any more of them around?" he asked Kunosh. The old man nodded.

"There are several more, but when they hear about this, they will leave and go back where they came from."

Nelson walked over and picked up the ers-gan again. He wasn't going to let it out of his hands now until he was sure he was safe. Then the significance of what Kunosh had said penetrated. "What was that? Did you say 'go back where they came from'?"

When Kunosh repeated, Nelson quickly asked, "Where did they come from? They're not part of your own people?"

Kunosh was silent and a little frightened for a moment. "Well," he said slowly, "they are from our own people, really. I was just—just—just using a figure of speech."

Nelson began to feel himself getting angry again. "Oh no you weren't!" he said slowly. "You have to stop and think to translate everything you want to say to me into English and you must mean exactly what you said. These people didn't come from Deimos, though they may look like your kind. Where did they come from?"

He hefted the weapon angrily. He had no love for these cowardly people. He realized that now that he had rid them of their old enemy, he himself represented a new menace—and possibly a greater one in their rabbity eyes.

Kunosh didn't answer for a while, but stood there, looking very upset and starting to wring his hands. Nelson noticed several of the blue-clad men beginning to edge toward the exits. He raised his weapon. "Stop, all of you!" he called. "Just sit down where you are.

Now that I've got all you Deimos leaders here, you re not going to get away until you tell me everything I want to know!"

The others hesitated, not understanding his words, but fearing his tones. Kunosh translated the command in a soft sibilant tongue. Shaking, the seven sat down where they were. Kunosh backed against a wall, pale and troubled.

Nelson turned to him. "Now, old man, I want to know just where these monsters' of yours came from!" But Kunosh merely stood, mute and shaking.

"Go ahead, tell him, you old fool," said another voice. Nelson glanced down. The speaker was one of the men in the red-and-black coveralls. He was sitting on the floor, his hands and feet tied, but he had recovered consciousness from the scuffle. He stared at Nelson coldly, without fear.

When Kunosh remained silent, the foeman spit. "Well, I'll tell you," he said. Kunosh gave an order and three of his compatriots suddenly lunged for the speaker. But before they could clamp their hands over his mouth, he triumphantly snapped out, "We're from the other moon!" A hand smothered his mouth, but the bound man bit down and the owner of the hand yelped and pulled it away just long enough for the word "Phobos!" to pop before he was quieted again.

Nelson felt himself going pale. His father and his friends were on Phobos—and if that satellite was also a honeycomb world, then by this time they might all be prisoners—or slain!

what Nelson would do, his men started to carry out the bound enemies. For a moment Nelson was uncertain. He realized that he couldn't entirely trust anything that these cowardly creatures might do. Then, as they started to carry out the man who had interrupted them, Nelson called, "Stop! Leave that one here. I may want to ask him some questions myself. He seems to speak and understand English."

Kunosh frowned, started to object, but seeing that Nelson was still by no means calmed down, waved his friends back. They propped up the red-and-black stripe-suited stranger on one of the low seats against the wall, though they still kept a grip on his mouth to prevent him from talking. The rest of the foemen had already been removed from the room.

Nelson nodded to Kunosh. "All right, you can start. Are you the lost Martians?"

The old man shook his head, went over to the now glowing wall panel. "No," he answered. "We did not come from Mars. We come from a world in the system of this star," and his hand caused a picture to flash on the wall screen.

A brilliant blue-white star shone against the blackness of space. Around it could be seen the disks of several planets, moving slowly around it. Kunosh pointed as he spoke:

"This is the star you people call Vega. Around it are seven planets, and on one of these planets our people originated."

On the screen, one of the disks came closer, enlarged until it filled the screen to show a small world, rocky in nature, crisscrossed with ridges of low mountains, many lakes of various sizes, two or three deep but narrow seas. A world by no means as beautiful or apparently as large as Earth, one without many plains, where green vegetation grew only on mountainsides, or in the innumerable twisting valleys between the gray crags of rock and cliff.

"This was our home world," Kunosh said. "On it we evolved from savages and we found our way to civilization and the culture that is the only true culture."

The scene swooped down to the surface of this world and Nelson could see villages nestling against the rocks, roads that climbed the mountains and tunnels that cut through to neighboring valleys. An industrious world, but still essentially one that seemed restricted to small communities. There was never a sign of anything like a large city.

"We took pleasure in boring into the mountains, putting our factories beneath the rock where they would not interfere with our small farming areas."

The scene dipped suddenly underground and before Nelson s eyes flashed a network of caverns and tunnels and rocky workshops where the little people of the Vegan race hammered and cast and drilled and made things. The scene changed, and Nelson recognized that it was an educational device designed to show progression, for the caves enlarged, the corridors from being crude, became wide and smoothed, the caves where men worked by hand now showed machinery of increasing complexity, puffs of smoke indicating the passage of steam power, then the yellowish glow of electricity and finally the white softness of atomic lighting. More and more it was clear, as the disk would rise in its view above the surface to show that the villages had not perceptibly changed, that the bulk of the life on this world was being carried on underground. It occurred to Nelson now that these people were more like gophers in their ways than rabbits.

"We spread our civilization over our entire world and we had a very happy world. We invented all that we needed and we did not need any contact with other worlds."

There was a curious scene shown. A strange squarish craft bouncing down from the sky on flaring rockets into a valley. Fliers of some sort emerging from it, their shapes concealed by bulky spacesuits. A delegation of the small pale Vegans meeting them, apparently denying them entry to the world, showing no hospitality, and the strangers leaving again in their ship, never to return.

"We were sufficient to ourselves. We did not welcome intruders with their crude ways and ugly thinking and horrible arts. Our own art and science were perfection, why should we mix it up with lower types?" Kunosh's voice began to reflect some of his fanaticism and pride, Nelson noted.

"But surely your people must have realized they could learn a lot of new things from other planets? Didn't you want to have spaceships too?" Nelson asked.

Kunosh turned toward him a moment, his eyes flickering in the glow of the wall panel. "Their new things stank of killing and violence. Their art was horrible and unsuited to our world. What we had invented was our own work and our own secret. Why should we give it to them in exchange for such trash?"

Nelson realized he was dealing with a type of small-mindedness that had never been seen on Earth. For a moment the thought of a world of such people gave him a chill. He shifted the ers-gun in his hand uneasily.

"Was there no war on your world? I should think that a world of small valleys would have many languages and cultures?" he asked.

Kunosh shook his head. "No. We never fought with each other, why should we? As for language, we have no record of more than one. Possibly all our people originated in one spot and moved out."

Nelson thought there was something slightly wrong about this, from what he could remember of language studies. "And possibly there was some dirty work done you'd rather not remember!" snapped another voice, and Nelson saw that it was the prisoner taking advantage of his captors' inattention. Again they silenced him.

The Earthling stared at the cold eyes of the captive, turned again to Kunosh, who was likewise glaring at the prisoner. "Suppose you let him talk. I've an idea he might help you get at the full story."

The old man seemed to be trying to keep his temper under control. Finally he barked a word and turned back to his panel.

"As I said, we never had any wars in our recorded history and we didn't want any. Our philosophers developed our culture along the lines of harmony. We looked on all forms of violence and compulsion as evil, as returns to the animal, and we carefully weeded out all such throwbacks." Kunosh could not resist throwing a nasty look at the prisoner, who glared back at him.

The screen flashed again over homes and scenes. It was evident that here was a world where nothing visible indicated weapons or warfare. Yet, somehow, Nelson did not feel that these were people with peace in their souls. There was something basically sneaky in their approach. They liked too well to hide their doings from the light, to travel in secret in tunnels, to conceal probably from their own minds the roots of their nature. Curiosity, the young man remembered from one of his instructors' lectures, was the root of man's development from the beast. These people must have had curiosity to have advanced as they did. If so, this curiosity would have forced them to space flight and to interest in their neighboring worlds. Instead they had rebufEed these visits. Why? Only one emotion suggested itself as powerful enough to overrule intelligent curiosity. Fear. Overpowering cowardice. Somehow, in their development, this trait had persisted, manifesting itself in their opposition to suggestions of combat, in probably erasing from their memory the many combats and struggles they must surely have won to have built their world culture.

Kunosh was talking. "We lived happily in our rocky world on Vega. We could listen to our neighboring worlds on our radios and receivers, but we had no desire to speak to them. We knew they had made contacts among each other—and that they had conflicts with each other. We saw some of them and were glad we had nothing to do with such monsters."

On the panel were scenes of space. There were fleets of little rockets darting against the blackness. There was a shot of two such exploding suddenly against the stars. There was a shot of several of the Vegan people staring in horror at a similar scene on what was probably a telescopic projector.

"The fact is that they had trade and friendship most of the time, and we were left out!" said the Phobosian suddenly. Kunosh whirled at him.

"That's a throwback viewl You're a filthy degenerate to think good of such a thing!" The Phobosian merely stuck out his tongue while Kunosh waved a fist.

The old man recovered his temper. "Anyway, we were happy and getting along, our noisy neighbors leaving us stricdy alone, and then the Marauders arrived!"

There was silence. On the panel, interstellar space showed. Then there came a moving glimmer of tiny fights. The scene sharpened and Nelson could make out black shapes, the dark forms of long spaceships moving in. And he suddenly realized that there were not just a few, but hundreds, even thousands of giant spaceships in that fleet!

"Our first indication of the cosmic plague was when some refugee spaceships arrived at our neighbor worlds. We saw them through our observatories."

The panel showed two or three odd craft circling into a Vegan world, accompanied by the squarish craft native to that planet. "These refugees came from stars beyond our own. None of our neighbors had ever developed star flight, but these strangers came among them with their terrible story. They had been war-craft of some far-off system, and one day there had come into their system this tremendous fleet of terrible black ships. These ships had destroyed all that came before them. They had landed on their worlds and out of them came huge armies of terrible creatures who robbed and burned, and killed everything in their way."

Kunosh stopped, his voice emotionally out of control. Nelson could feel the silence in the room, the horror at the scenes which were being shown on the panel. There, before his eyes, he could see cities burning and falling, huge masses of shapeless terror swamping the fields and houses, crowds of terrified people fleeing vainly only to be burned down!

He caught his breath. "Are these actual scenes?" he asked.

"No," Kunosh replied. "How could they be? They are artists' reproductions of the accounts given by the few who escaped. But they are faithfully made.

"Our ancestors were disturbed at this, very disturbed. Our neighbor worlds began to arm against them. They were devoting all their efforts to building war fleets and defenses. But we were not going to do that. To do such terrible things would be to sink to the level of animals. It would destroy our civilization. And besides it was obviously futile. These Marauders, as we called them, apparently were traveling the universe to ruin and pillage and rob. There were thousands of their big ships and they must have been armed beyond all our conceptions!

"We didn't know how long it would be before they arrived at Vega and killed us all! We thought we had a few years, and we finally decided that the only smart thing to do would be to flee. We didn't have spaceships but we knew all about them. We knew we could make them. Our science was advanced enough.

"We held a great conference in our world and we talked it over until we decided what to do/'

The scene showed a large underground cavern with hundreds of the rabbity men in heated debate.

"We built two giant spaceships in the form of two great big spheres. These ships were large enough to carry many thousands of people. Inside them they had room for factories and storehouses, synthetic farms, and all the things needed to carry on life entirely within them without need of sun or surface."

The screen showed two tremendous frameworks going up, being filled in, being surfaced. Nelson gasped as he realized that he was looking at ships larger than any about which he had ever dreamed. By comparing them with the mountains nearby, he saw that the two ships towered above them, that the men who were building them seemed smaller than ants. Why—he gasped—they were the sizes of the two moons of Mars I

His suspicion was confirmed as the artificial globes were surfaced. The outside of the two vessels was made to look like barren rocks and cold stony plain. Before his eyes the contours of Deimos and Phobos took shape!

Kunosh went on: "We were just in time. As we were finishing our escape craft, the first of the Marauder ships was sighted."

The screen showed a single advance scout, long and black and deadly-looking, flashing into the blue rays of the Vega system. A cloud of squarish battlecraft from the other worlds rose to meet it, but the black ship easily evaded them and disappeared in the direction from which it had come.

"Plainly our system was to be the next victim. We had no more time to lose. So we manned our two ships and took off."

Nelson watched columns of men and women and children disappear into the interiors of the two great ships, while loads and loads of stores and things were crated in. Then, from their rocky valleys, the two towering spheres lifted slowly without sign of rocket or jet. They moved up in the sky and vanished.

Kunosh continued. "To travel between the stars takes more than the lifetime of any man. We could not build small ships and go. So what we did was to build two tiny worlds in which we could continue to live and work and have children while they traveled the long distances to safer regions of the heavens. Our trip across space took ..." he paused to mentally calculate his figures into terms Nelson could understand ". . . about three thousand of your terrestrial years."

There were glimpses of life inside Deimos and Phobos as they moved together across the empty stretches of interstellar space. Nelson could catch views of the two worldlets, honeycombed with life, with anxious leaders viewing the stars toward which they drove, with several glimpses of huge machinery in the core of the spheres, driving the two vast craft by some means not yet discovered by humanity on Earth.

Then finally the screen showed a yellow star approaching and growing. Several planets were picked out circling it, and Nelson recognized the ringed vision of Saturn. The two huge craft entered the solar system, picked their way around it and came close to Mars.

"Of all worlds, this one seemed the best for us," said Kunosh. "We looked at Earth, which was more like our home world, but we found it already filled with people and animal life of all kinds."

Nelson was suddenly startled as the panel swooped down on Earth, and before his eyes plunged through cloud and rain to pick out the jungles of Africa, to spot a tiger leaping upon its prey in India, to flash briefly into a nest of snakes in some South American tree-top, and then, to his wide-eyed amazement, to swoop along an open field of green, to hover for a few incredible minutes over a battlefield on which men in plumed hats and curving metal helmets fought. Men dressed in gleaming breastplates, lugging cumbersome blunderbusses which they set up on tripods and fired at each other amid clouds of black smoke. He saw snorting cavalry go thundering across the field, while Cromwell's Roundheads and the Cavaliers battled furiously with swords.

"That must have been about the seventeenth century," remarked Nelson, realizing that he was seeing an actual visual record of some historical battle.

"About four hundred of your years ago, anyway," said Kunosh.

The panel shifted to Mars, swooped low over its surface, over its deserts and green continents and cities. It was as quiet and deserted as ever. "We found this world, without violent weather, without inhabitants. We found the cities waiting to be taken and lived in and ready. We decided to stop, to put our two ships into orbits around it and watch to see if this was no deception."

Now the vision of Mars steadied to that as seen from the surface of Deimos. Nelson said then, "Then your two ships have been moons of Mars for four hundred years and still you never colonized it!"

Kunosh looked at him gravely. "We are a very cautious people," he began, only to be interrupted by the Phobos captive who had been quiet up to this point.

"You mean foolish and cowardly!"

Kunosh angrily shook his head. "Cautious. We didn't know whether the Marauders were going to visit this system someday and we didn't know whether they had followed us. If they had we wanted to be ready to make our get-away without delay. Again, we were suspicious about this empty world. What had happened to its inhabitants? Were they wiped out by some dreadful plague that would do the same to us? Were they hiding, waiting to leap out and kill us all once we settled down? Anyway, until we found out, we were determined to take no chances."

Kunosh paused awhile, picking his words. "There was another factor as well. Our study of historical development, of our cruder neighbors in the Vega system, showed us that you Earthmen were on your way to discovering the secrets of nature. We knew it would be but a matter of a few more generations before you would begin to hit on the rocket method of space flight. We knew that it would not be long, in an astronomical sense, before you too came to Mars to explore. We had no desire to mix with you or to engage in trade or perhaps get involved in arguments or warfare. If we did any of these things, it would change our ancient way of life; it would destroy our own civilization!"

The captive Phobosian burst out, "Aw—nonsense! All that thinking is wrong! People with courage and honor can obtain the respect of others with honor and can benefit by such contact. This idea of always being in hiding and avoiding other civilizations will be the death of all our people!"

Kunosh looked at the captive thoughtfully. "Yes," he began, then turned back to Nelson. "What this enemy has said has become much the prevailing way of thought on our other spaceship, the moon you call Phobos. There, for some reason we can't understand, the ancient tried and honorable ways of our ancestors have been corrupted and perverted by such thoughts as these. The people there, though once our brothers, have split from us in views. From the first, they were the advocates of landing on Mars and taking a do-or-die stand. Their weaklings got the best of their true thinkers and advocated an end to running. They have even dared to send spies to Earth, disguised as Earthlings, with false faces and false hands, to keep an eye on the intentions of its inhabitants. They have been on Mars itself, prying into the works there, watching you colonists. In fact, I even think they started the business on Earth of suggesting your colony's abandonment."

The Phobos man laughed. "We didn't. We didn't have to, and in spite of your fears, we've never interfered with Earth's politics. Oh, maybe we made a few mistakes by being spotted, but nothing much came of it. One of our best agents got into this young man's room when he was coming back to Mars. If he had found what he was looking for, we'd have known about

The whole mentality was unhealthy, he reflected. A thought occurred to him:

"Sometime in your past, before you were civilized, you must have fought. You couldn't have conquered even the wild animals of your native world without some spark of violent courage. And besides, where did this ers-gun come from? It's a weapon ..."

Kunosh shook his head. "If there were such traits amongst our primitive ancestors, they were animal characteristics which we have carefully weeded out and overcome. As for the weapon you have in your hands—it is something one of the first space visitors from our neighboring worlds around Vega left behind. We put it in our museum of horrors and that's where I took it from."

Young Parr hefted the odd gun and looked at it. "What does it do?" he asked. "You never told me."

The Vegan answered, "I don't quite know myself. I prefer not to think about such awful matters. We ourselves have no weapons of our own, unless the degenerates of Phobos have made some since. There might be such on their ship."

Nelson's eyes popped. "On what? On their ship! But, of course, they must have a ship here on your moon! Where is it? If I can get to it, I can use it to go back and warn my friends."

Kunosh looked horrified. "Didn't I tell you that you must never leave here? We can't let you go!"

"And you can't stop me either!" yelled Nelson angrily. "You won't use force, and I've got your only gun." He pointed it at Kunosh. "Now take me to the Phobo-sians' ship. The one they used to come here."

For a moment it seemed as if the old man was going to refuse. He had no reply to Nelson's challenge, for it was true, the old Vegan would never stoop to using force. But then he glanced a moment at a dial on the wall, which looked as if it were a register of time, bit his Hp, and turned.

He left the room with Nelson at his heels holding the m-gun firmly. They walked through several halls with the natives again shrinking away from them as Kunosh warned them of the situation. They walked until they came to a shaft leading vertically upward. There was a moving chain of platforms, like the scoops of a dump truck, going up the shaft. Kunosh stepped on one and Nelson quickly joined him. They rose slowly in the enclosed space of the shaft.

"Where does this go?" asked Nelson.

"This goes up to our own spaceship port, which is in a cavern just underneath the surface. We have several craft there which we use between the two moons when we need them. The Phobosian ship must be there."

The shaft continued its rise until it came to a stop at a small room cut in the rock. They stepped out of the scoop belt and Kunosh opened one of their sliding doors. They came through a second small chamber, which Nelson recognized as another airlock. They stepped out into a huge hangarlike hall where a number of curiously designed craft rested. They were somewhat wider and squatter than terrestrial designs, and in one corner was one that was very nearly cubical.

At a ship near the far wall, Nelson caught sight of several men in red-and-black striped suits clustering about the open door. "Hey!" he grabbed Kunosh by the arm. "Those are our prisoners! They're getting away!"

The old man stopped him. "Of course. We're sending them home. What did you expect us to do? We're not going to do anything as bestial as locking them up or even killing them."

"Blast it!" shouted Nelson in fury. "You cowards!" He dashed for the Phobos craft, shouting to the men to stop or he'd shoot.

The men in red-and-black stripes glanced back at him and, instead of stopping, rushed to get into their ship. As the last one piled into the open door and started to slam it shut, Nelson stopped, grabbed up his ers-gwi and aimed it.

Behind him he heard Kunosh give a gasp and turn to run back to shelter in the shaft's airlock room. For a split second it occurred to Nelson that if this unknown device fired an atomic or an explosive charge, it might mean his own death also in that enclosed space, but he was past worrying. These men had killed Jim Wor-den and were a menace to his father's expedition. He touched off the trigger button of the gun.

Nothing happened.

The door of the small spaceship slammed shut. There was a whirring sound and a cleft appeared in the stony ceiling of the chamber. With a whoosh the air in the place started roaring out into the near vacuum of the outer surface of Deimos. Nelson stood staring down at the weapon in confusion. Desperately he began punching parts of it, in hopes that somehow he would hit on the means of making it work. But nothing happened.

The Fhobos ship gave a vibration, lifted gently and hurled itself upward through the wide roof opening and into space, en route to its Phobos base.

Nelson felt his breath being sucked away, and he hastily closed his helmet and activated his spacesuit air system. The spaceship was gone and Kunosh was safely out of sight, protected by the airlock.

For a while Nelson debated what to do. He could leap out of the cavern through the roof hole, which was now beginning to close. Once on the surface, maybe he could signal his friends on Phobos. On the other hand, it might be too late. Once the escaped men reached their home, they would waste no time seizing the Earth expedition they had so carefully avoided during the months of its stay on their surface.

On the other hand, if he went back to Kunosh, he might manage to learn how to run one of their other spaceships and thus make his own get-away. Then it struck him that surely the Vegan colony on Deimos had some means of communicating directly with then-sister starship of Phobos. Why, there must be a radio link or something even more advanced!

He started toward the airlock doorway as the cavern roof sealed shut again and he heard the whispering sigh of air being pumped back in the hangar. He studied the ers-gun carefully as he did so, and regretted that he had not taken the time to do so while Kunosh was telling the history of his people.

It looked like a dangerous weapon, but try as he would, no knob would turn, nothing would move on the thing. Now he poked his finger into the depression that opened the airlock chamber. Kunosh stood there in an attitude of listening. He seemed surprised to see Nelson.

The young man grabbed his arm. "How does this thing work?" he snapped. "It didn't go off! Suppose your enemies had guns and I had needed it to save your people?"

Kunosh shrugged. "That was the chance you took. After all—you are really nothing to ones as advanced as we. As for this ers-gun ... well, you don t think our ancestors would be so foolish as to keep such a thing in existence. This is a museum model, a dummy good enough to represent the real thing and therefore good enough for our museum of horrors. The original working reality we destroyed centuries ago!"

Nelson gritted his teeth in frustration. These spineless rabbits! These conceited gophers! he thought. Well, he could always use the ere-gun as a club!

He reversed the weapon, hefted it threateningly. "You must have means of talking with the Phobos star-ship?" he said, and when Kunosh nodded slightly, added, "Well, then, take me to it!"

The old man silently turned and the two went back without further word. Down the descending side of the scoop shaft, out through the halls, and back to the very same central governing room they had been before.

The clerks and directors—or whatever they were— were back on the job again. At Nelson's entry they halted the routines they were engaged on and then slowly returned to them, keeping an eye cocked toward the stranger.

Kunosh went over to the far end of the room. There was a large wall panel there and he pressed some studs. The panel flickered, glowed to life, and settled down. Before them was a room identical in every way with the one they were standing in. The two starships must have been built on the same plans save for the difference in size.

In this Phobos room, men in the striped clothing distinctive to that branch of the Vegans were gathered in heated discussion. As they noticed that the inter-moon panel was in operation, two of the men detached themselves and strode over to face Kunosh and Nelson.

Young Parr saw at once that these men had a confidence and hardness utterly lacking in the rabbitlike creatures of Deimos. The leader looked coldly at Kunosh and said something in their native tongue. Kunosh didn't bother to answer him, distaste for his opponent chieftain evident on his face. He jerked a finger to indicate that it was the Earthling who wanted the interview.

The Phobosian looked hard at Nelson, changed to English. "Oh, one of the two that got away. I didn't believe that old scarecrow had the nerve to capture you. Where's your friend?"

Nelson stared back at him. "He was killed by your cowardly gang ... or didn't they bother to tell you?"

The other simply stared at him for a moment. He shifted his glance to Kunosh, who was biting his lip. "My—gang—as you call them—killed nobody. If we'd wanted to kill you, we could have done so easily anytime in the last few months. Why should we have to do so now?"

For a moment Nelson was speechless. "You're lying!" he said. "Your men sneaked up on Jim Worden and attacked him when he wasn't looking. Then your men smashed our ship!"

The Phobos leader turned to Kunosh, said slowly, "So you do know how to use violence when you have to, you old hypocrite! Your gang of weaklings make me sick. All your prating about bestiality and throw-backs just to cover up your own bred-in-the-bone rottenness."

A cold chill ran down the young Earthling's spine. Could it be, could it possibly be that the killing had been done by the Deimosians, those rabbits? And it suddenly dawned on him that it had to be so. What the Phobosian had said made sense. They could have killed them anytime, certainly they didn't need to follow them and do it on Deimos ... an act that would alienate their cowardly kin even more. And then there was the dishonest business about the ers-gun ...

Nelson drew away from the old man. He spoke to the Phobos chieftain, "Where's the rest of my expedition? My father, Gutman, and the others?"

The other looked at him. "We took them prisoner as soon as we saw they had track of our Mars operation. They're safely under guard—and we have thrown overboard our ideas of hiding and running." He turned to Kunosh, addressed him:

"We're sending a ship back to pick up this Earth-man. We want him where we know he won't escape and where you won t be able to kill him when he's asleep either! Tell your rabbits to grab him!"

Kunosh stirred uneasily. He whined something back through the panel in his native tongue, but the Pho-bosian merely angrily repeated his request.

Nelson hefted the weapon. As a club, it could do plenty damage if the Deimosians attempted to carry out that order. The men in the room behind him had come to their feet, were slinking slowly closer to him. The Earthling turned his back to the panel. "Don't try it!" he warned. "I can do plenty of damage if you dare touch me I"

The little crowd of Deimosians, their faces pale and twitching, their mouths working, continued to close in on him. Cowards or not, they were going to seize him. And Nelson realized now how true the Phobos charge was. The Deimosians could kill if they had to and undoubtedly were the slayers of Jim Worden. What a fool Kunosh had made of him!

He swung his weapon threateningly. The band shuffled closer to him, stood gathering their courage until they would leap at him in a burst of final desperation.

The communication panel to Phobos was still open, and several more of the striped-clad men had gathered before it on the Phobos side to watch the interesting spectacle of their cowardly brethren put to the test. Nelson could hear comments in their native language through the panel.

But as he braced himself for the assault, he heard a new note through the panel. The sound of someone running into the central Phobos room and shouting something. He heard a sudden rusding as the men on that moon seemed taken by a new thing. The young Earthling risked a glance back over his shoulder.

was holding another of his governing board by the shoulder and shouting at him. The other men were frantically running back and forth, apparendy unable to recover their senses. The news had struck them like a bomb, had disrupted their entire mentalities, so geared to hiding instead of action.

Bewildered and entirely overlooked in the turmoil, Nelson Parr sat down and simply watched. What was he himself to do? Obviously he ought to take advantage of this confusion to escape—but where could he go?

He could probably find his way back to the Deimos spaceship hangar, but once there what would he do? He doubted if he could run one of their ships and if he did manage to, where would he take it? He couldn't go to Phobos because that would simply be delivering himself from one captivity to another one. He could get to Mars, but it was deserted. He could probably keep himself alive there, but that would not remove the danger of the Marauders finding him.

Actually his most urgent task, his duty, was to find some way of notifying Earth of the danger, readying Earth's defenses. It seemed, from what he had seen and heard of the oncoming pirate horde, that the best warcraft Earth could muster would hardly have a chance. He knew that really there was no chance at all. Warcraft for space was something almost unheard of. It had been speculated upon in stories before space flight really got under way, but the cold reality of interplanetary flight had brought no actual need for them. There had been no other planetary civilization to fight, no savage natives of other worlds, and the expenses and complexities of astral navigation had made space piracy an impossible fantasy—besides, what was there for such pirates to steal? In short, there had never been any reason for space-going warships.

On Earth itself, warfare between nations had been successfully abolished for over a hundred years, and save for a few ceremonial guards of honor there were really no soldiers. There were police forces only, and there were some stores of old armaments in various government warehouses and vaults.

At least if Earth could be warned in time, the leaders might hastily equip some spaceships with guns, or with means of launching atomic torpedoes. They might at least arm the people so that any attempt by the Marauders to land would cost them plenty.

In any case, Earth had to be warned! But how? At the moment it was already on the other side of the sun, well over two hundred million miles away, out of sight of both Mars and the invading fleet. No radio, not even such super-radios as perhaps the Vegans might possess, could possibly reach Earth across the interference of the sun.

The only way to warn Earth would be to go there ... and that seemed to be an impossible hope.

The Deimosians had recovered a little of their senses, though they were still white and shaking. On the Phobos side, a serious conference was already taking place. Kunosh walked over to the panel and switched it off. He rapped for order, yelled a command, repeated it, and finally got the attention of his men.

They slowly quieted down, gathered around him. Kunosh talked swiftly, heatedly. There was little debate as the stunned councilors listened to him. Nelson^ sitting at one side, assumed that this was a hasty conference to discuss ways and means of saving themselves. He got up, went over, and broke in:

"I want to say something, Kunosh. If you are deciding what to do, I have a suggestion to make."

The old man glanced at him sharply. "This is an important meeting. What can you have to say?"

Nelson spoke swiftly. "Your only hope of fighting off the Marauders is to throw in your lot with Earth. Earth has a huge population, great factories, and plenty of courage. If you come to Earth, warn the people, they will welcome your aid, give you shelter. With the special information you can bring, Earth can find a way to build defenses. Even if they can't, they can make it so hot for the pirates that they'll go away. Earth needs your science; you can use it to bargain for a place to settle down, a permanent home.

"Take Deimos across space to Earth while there is still time to outrun the Marauders. You can't hope to hide here forever, especially since they may have records of your two moons from the Vega days, may be looking for you!"

Kunosh listened to him, frowning and shaking his head. He spoke to the others in the room, apparently translating Nelson's words. The councilors glanced at him with horror. Those nearest him drew away. The old man brushed a hand over his brow.

"No! No! That would be as unpleasant to us as being captured by the devils from the stars. You are as strange to us as they are! We are not going to break the stern traditions of our ancestors by trying to fight or by giving strangers our ancient secrets 1 There isn't a true Vegan here who wouldn't agree with me!"

The obvious fear and hatred reflected on the faces of those in the room made Nelson realize the futility of arguing with these incredible cowards. These rabbits were vicious, they were panicky, and beyond sane reason. "Then what can you do?" Nelson demanded truculently.

Kunosh paid no further attention to him while talking heatedly to the councilors. Then, as the meeting broke up with the room emptying as the others scurried from the chamber on urgent missions, he looked at Nelson.

"Were going to run for our lives! We're going to activate the engines of this starship world and race away from this solar system and away from the Marauders. Once we're in the deeps of space at full speed they'll never locate us. We'll go on until we can find a star or planet somewhere where they can't ever find us. Even if it takes thousands and thousands of years, we'll keep on going!"

Nelson gasped, "But when are you starting? What about me? I don't want to go along!"

Kunosh waved a hand indifferently. "Do what you want. Do you think we can be concerned about you now?"

Nelson grabbed him by the arm, swung him around. "I don't give a rap if you don't care, but I do. I want one of your spaceships! Now! Lead me to it, or I'll break your arm!"

Kunosh winced in terror. "All right, all right! You still have an hour before we can start Deimos moving. Go ahead up to the hangar, take a ship, and go! Leave us alone! We don't want youl"

Nelson held on to his arm, brandished his weapon. "You'll come along with me until I get the shipl I'm taking no chances with a lying sneak like you! Come on!"

He dragged the squeaking old man out of the chamber and force-walked him back through the halls to the shaft scoops. Around him, in the mazes of the star-ship moon, there were wild scenes of panic. Men and women were scurrying back and forth frantically and wastefully. No one seemed to be in control, no one seemed to be able to keep his head. If men were busy at starting the actual preparations for running away, it was not evident.

Nelson and Kunosh reached the shaft, got on it, moved upward. "What will Phobos do?" the young man asked as they rose.

"I don't know and I don't care," snapped back the Deimosian. "This is a good opportunity to leave those degenerates to their own undoing. At least that'll be some good coming out of this!"

They reached the hangar, passed through the locks. Inside the subsurface area there were several craft. To Nelson's eyes all seemed small and designed only for short intermoon flights. As the old man seemed indifferent as to which one he took, he insisted on walking over to each and examining all of them. He ignored Kunosh's protests of impatience and time lost.

He could reach Mars with these ships, but apparently they were not built for longer journeys. To strand himself on the red planet would be an escape for a short while but would be no help to Earth. Then in the corner he caught sight of the ship that was so oddly cubical. Hastily he closed in and walked around it.

It was visibly larger than the other craft, and now that he was so close, he could see that it was quite different in almost every respect. The metal was darker and slightly pitted as if from extensive flight. There were a few narrow squarish portholes, dark and glassy. And there were odd projecting bumps that looked suspiciously like guns!

"What's this?" he asked. "It doesn't look like one of your other ships at all!"

"It's a ship from another Vega world. We . . . took it with us as a curiosity when we left Vega. It's a vile battle cruiser of the Malakarji people. We use it as a horror exhibit for our children."

Nelson looked for the entrance, found it, a square doorway, set firm in the surface. "Open it!" He shoved Kunosh toward it.

The Vegan pushed down a plug set in the center. The door suddenly pushed outward like a cork, swung upward. "The entire ship has controls like that. We've kept it in working order," he said. "You can take this one, if you want to, only be quick!" He stood aside and waited for Nelson to go in. But the young man was too smart to be caught.

"Oh no," he said, "you go in first. You'll show me everything I need to know before I'll trust you out of my sight!"

"Bah!" Kunosh stamped his foot, but he climbed into the airlock of the odd ship, with Nelson at his heels.

Inside, the structure was amazingly like a little house. The driving machinery, which was clearly not rockets but must be on the order of the advanced controls used by the starship moons, was apparently housed in the ground floor. The living and storage quarters were evidently on the second and top floor of the little cube.

Nelson found himself entering the chamber on the bottom floor and was in the midst of bright, gleaming, massive machines at whose nature he could not guess. There was a huge thick wheel circling the entire lower floor and that was probably a major part of the drive. Perhaps magnetic currents had something to do with it, or the paragravital flows which recent science had begun to detect. The two climbed a short ladder to the upper floor.

Here there were several oddly placed rooms. The control room was in the exact center of the ship and looked out through a rounded transparent bull's-eye directly overhead in the roof of the cube. Panels in the walls of the room gave views from all four directions, though the ship was apparently blind from its basement side. Evidently it flew directly upward, and probably caused a semblance of gravity down against its floors when in normal flight.

Around this central control room were about eight small chambers, obviously sleeping, eating, and storage quarters. On each side and above, there were what were quite obviously cannon emplacements.

Nelson made Kunosh explain the layout. The old man insisted that the ship was ready to fly, that apparently its source of power did not require fuels other than atomic piles which when once installed would supply power for countless thousands of years. The old man pushed in a plug on the tablelike main control board. Immediately a soft light glowed in the room, the wall panels lit up to show the outside walls of the cavern. Several lights glowed in various colors on the stud-covered table. Hastily Kunosh pointed to each, stating in turn, "Power, direction, acceleration, deceleration, heat, light, airflow," and so on.

It was apparent to Nelson that the ship was indeed in working order. If it was atomically powered, then it ought to be able to make the trip to Earth! He didn't know how fast it could go but it was at least a hope.

Kunosh was hopping up and down, anxious to leave. Satisfied, Nelson nodded, and the old man scurried down the ladder and out the door. Through one of the wall panels, Nelson could see him run out of the hangar. Nelson pushed the plug that closed the airlock door and sealed the curious ship.

Let's see, he said to himself, reviewing the various controls. Where's the communications—or isn't there one? He looked about. Set against one wall was a circular glassy device, the typical viewplate. Several plugs set at its side were the obvious controls. He plugged one at random.

The screen flickered, steadied. A face looked out at Nelson. It was the face of his father, John Carson Parr!

"I'm on Phobos as you see, deep in its center. I guess you know now what these two moons really are. We heard something about you from the men with whom you had that fight. They were quite angry here about your interference, you know. Apparendy that old schemer Kunosh took you in completely."

"Yes, yes," Nelson nodded. "But tell me about you and the men. What happened to you?"

The elder Parr glanced down, presumably at his watch. Looking up he said, "There isn't very much time, but I'll try. We weren't worried about your absence for about twenty hours, when it was about time for you and Jim to return. When you still failed to show up, we began to get uneasy. We tried radioing you when Deimos came into sight, but we got no answer at all.

"We were keeping an eye on Deimos for your return and were watching it by telescope when we saw a fight appear on the surface and something take off. We supposed it was you two and tried to keep track of the object but lost it amid the stars. WTien you failed to make a landing here we got worried again, for the trip between the two moons at that point should not have taken long. We gathered to discuss whether we ought to take off and go to Deimos to see what had happened there, when we heard someone knocking on the outside of our space-lock door.

"Naturally we assumed it was you at last. We got the lock open and a bunch of men dashed in dressed in spacesuits and helmets. We hardly had a chance to make a fight of it when they were all over us and had us prisoner.

"They took us out of our ship and down underground. I suppose the insides of the two moons are pretty much alike. Anyway it's a huge spaceship here, a star-going spaceship ten miles in diameter capable of carrying tens of thousands of men, women and children and supporting a whole series of generations while the ship crossed between stars.

"The leader, Doldnan, talked with us after they had installed us in a fairly comfortable guarded room. He seemed a decent sort, explained that they were engaging in preparations for moving their whole population to Mars and making their home there. It seems they had been watching this world for centuries before getting up the nerve to do it.

"Doldnan told us that they had not intended touching us on the surface, figuring that they didn't want to do anything to make Earth angry. But when their delegation returned from Deimos, one they had sent to try to persuade their people there to join in the colonization scheme, they heard what had happened to Worden and how Kunosh had put the blame on them. So Doldnan said they had to go upsurface and grab us before we got some sort of wrong report and try to take revenge."

Nelson nodded. "Kunosh managed to make the Phobosians the bad ones all right. He said they had seized the moon by force."

John Parr shook his head. "Actually he wasn't telling the truth. The men from Phobos were only talking and arguing with Kunosh's councilors when you burst in and hit them. If you hadn't been along, Kunosh and his men would have had to do the dirty work themselves—but they always prefer to have someone else risk their lives. They wanted to spread bad blood between Earth and the Phobos people."

Nelson was puzzled. "I don't quite understand. Kunosh claims the Phobosians are Vegans who deserted their old traditions of hatred against force, who have become desperate and vicious."

John smiled a bit and cast a glance behind him. "To tell you the truth, to a certain extent Kunosh is right. Originally all the Vegans were like him, cowardly, slippery, and convinced of their own superiority. That's why the Phobosians did nothing for so long about taking over Mars. But the last couple of generations here have been watching Earth and our Mars colony and taking heart. Doldnan told me their spies reported favorably of our scientific integrity and peaceful intent. They have been debating this matter for a long time, and only very recently has the anticow-ardice faction won control of Phobos. On Deimos, however, the most fanatical supporters of the old views clustered and prevented even the debate from reaching their populace. The two moons have barely been talking to each other for the last generation.

"Don't get the idea, though," the elderly space explorer hastened to add, "that the Phobosians are regular wildcats. Actually they're almost as cautious as their smaller moon kin. They can't quite get over the customs of ages of rabbitlike existence. They don't like violence any more than Kunosh does, but they have enough sense to face up to a fight if they have to."

Nelson suddenly remembered his position and his father's. Time was running out and he was still standing in the controls of this strange ship while danger was rushing on them all.

"Yes, Dad. But what are you going to do now? I tried to talk Kunosh into taking Deimos to Earth and helping us fight off the Marauders. Gosh, Dad, with the science they've got in this moon we might have a chance! But I couldn't make him agree. They're going to start the starship up and run away!"

John nodded. "When they discovered the Marauders coming, Doldnan managed to keep his people from too much panic. They held a big conference, then called us in. After they'd explained the problem, they themselves asked us if Earth would give them protection and refuge in exchange for their scientific secrets. Of course we agreed, urged them to take their moon to Earth as fast as possible. I do have some authority as leader of the old Mars colony and as head of this expedition. And the stuff these people have here-well, some of their discoveries will give us a big boost! You should see their space drive alone! Imagine a drive, nonrocket in nature, that can move a ship this size across dozens of fight-years!"

Nelson was thrilled. "Shall I join you? What do you think I ought to do? I've got this spaceship though I don't know its powers."

"Yes," said Parr, and turning away from the screen, conferred briefly with Doldnan. He turned back hastily. "You'll have to start at once, son. I'm told our moon has been in motion for the past half hour already, starting to swing out to make a race for the Earth. We're on the sunward side and going to race in, cutting inside Mercury's orbit to swing around and out again to join Earth on the other side of the sun. You'll have to outrace us, because Deimos is on the outward side of Mars now and if Kunosh makes good his escape plans it will start outward at any moment."

"Gosh, you're right." Nelson jumped to the tablelike control board of his strange ship. There were flickering lights on a curious panel there, but he could not decipher them. Doubtless the original designers of the ship had a code that told them what their ship's detectors indicated, but the Earthling had no time to figure it out. He glanced through the windows of the ship. He was still inside the hangar, but glancing upward he saw that the open dome was showing a visible motion of stars.

He stared a few seconds at the visible sky and realized that the motion of the stars was different from what it should be in the normal orbital motion of the small moon. Kunosh had started the starship going! Every precious second wasted now would take him farther away from Earth, farther away from a rendezvous with Phobos.

Nelson went back to the telescreen. He saw that his father was busy conferring with several of the native councilors. "Good-by," Nelson called. "I'm going to take off. I'll try to catch up with you as soon as possible, if this ship can do it. Call me later!"

His father glanced back, waved. Nelson switched off, ran back to the controls. He could feel beneath his feet a curious vibration—the whole moon was undergoing a series of tiny quakes as it was being shaken out of its orbital inertia, forced to respond to controls that had not been used in hundreds of Earth years.

Hastily he checked his control plugs, reviewing Kunosh's hasty words. He wondered if the old man had lied even about this—it wouldn't be past him to do that. Well, he had no other chance but to try the plugs. He pushed the plug that was to seal the ship and was pleased to hear the far-off thud as the outside door slid into place. A light glowing on his board confirmed that and added to his knowledge of the controls.

He glanced upward and saw that the hangar was still open to the skies. Evidently Kunosh, who could have closed it and made trouble for him, was sincere in his desire that the Earthling go away. Nelson punched in the starter plug and felt the ship begin to vibrate on a tune of its own.

Somewhere in the engine floor below him there was a high-pitched whine that settled down into a low humming. There was a smell of ozone as currents started to flow into bars and condensers that had been idle since before the Pyramids were built. The ship seemed vibrant with its own life, seemed as if it were poised on its toes, ready for a leap into the void which was its natural surrounding.

Nelson punched the accelerator button, manipulated the hand bars below it. The ship gave a light jolt, and Nelson felt the strange sensation of pressure against his feet. He saw the cavern walls suddenly slip downward and in an instant the outer surface of Dei-mos passed in view and vanished below. He glanced to the side windows, saw the cold gray surface of the little moon spread out, and he directed the cubical ship upward, steadily accelerating.

His eyes took in the control panel and he watched the various lights shift thereon. Quickly he recognized a little white square in the center as indicating his own ship. To one side a large red mass was gathering and changing in color. This must indicate the moon he was leaving. He recognized the system as very akin to a radar board, though apparendy the Malakarji Vegans used a color system to indicate different bodies. An arrow of red pointed steadily to one side—and he recognized this as the Mars direction. Nelson nodded to himself—he wouldn't have much trouble with this ship, even though it did seem to be blind on the underside.

He brought the ship to a hanging position near the moon while he studied the area of space in which he found himself. It was as his father had said. Phobos was on the sunward side of Mars, out of sight in eclipse by the bulk of the red planet, now dark beneath Nelson's gaze. The sun could be seen by the edge of its corona peeking from one hemisphere of Mars.

Deimos was on what could be termed the outer side of Mars, facing away from the sun. Its position in relation to die oncoming Marauder fleet was at right angles, the enemy ships coming in a full ninety degrees removed. It was apparent already that Deimos was farther away from Mars than it had been before.

Kunosh was taking his moon into the empty reaches of outer space—directly away from Earth, from Mars,

this drive, which never lasted too long, the rest of the trip would take place in free fall—where there was no feeling of top or bottom, where floor and ceiling were the same.

On this odd vessel there was always one gravity acceleration and no free fall. Perhaps not exactly one gravity, for Nelson felt singularly light. The planet for which this ship had been designed must have been smaller than Earth, its gravity somewhat weaker, and its controls adjusted accordingly. Still it was a pleasant feeling for the young man, who had been so long virtually weightless.

Nelson watched the heavens as his cube tore along. Deimos rapidly diminished in size, became a white dot, and vanished amid the stars. Mars did not change much in diameter, but the sun was rising over its disk as Nelson's ship rushed away from its shadow into the direct rays of the sun. That body assumed at last its usual appearance—a blindingly brilliant white ball of light, surrounded by a waving glow of fiery projections that were its coronary discharges. All this appeared against the jet-black airless sky of space!

Nelson searched the sky for a sign of Phobos. This proved a difficult task, for as that tiny body was between the sun and himself, it was always the unfit dark side that he would see. He could hope to see the runaway moon, therefore, only by the manner in which it might black out the view of stars whose light it crossed. And as the moon was also heading almost directly sunward, always the bright glare of Sol would hurt the eye of the searcher.

It didn't take too long for the cubical ship to get clear of Mars' bulk—and it dawned on Nelson that its speed of one gravity was an illusion. Inside, this acceleration effect remained fixed, but plainly the craft had a greater capacity for speed than that. Somehow this extra pressure was deflected or absorbed so that it never affected the interior of the cube. Another invention that would immensely improve the art of space flight—if there was such an art left after the Marauders got through with the solar systeml

Nelson studied the control board again to try to determine what were the equivalents of speed and pressure indicators. He found a glowing bulb of green that had originally been very dim, was now fairly bright, and seemed to be growing stronger all the time. Carefully he adjusted the acceleration plug and the glow softened. This, then, was the speedometer system, and the young man used it to level off at a steady rate of speed until he was clear around Mars and heading in the proper direction.

It occurred to him that the builders of this ship must have been a keen-eyed race if they could depend on slight shifts of color intensity as a reliable scientific guide.

Clear of Mars, he again turned the craft, experiencing the odd second of tilt, and this time pointed the roof of the ship almost directly at the sun. He pulled the accelerator plug out and watched the green bulb grow brighter until it became almost blinding.

For a moment he bit his lip as he realized that he still had no way of knowing just how fast he would be going and therefore just how and when to slow down or shift. This was going to be a very dangerous business—he was, in fact, flying almost blind and it would take a miracle of sorts if he could bring this ship into port again!

To navigate through space one had to know not only the exact whereabouts and speed of your objective, but a very definitely exact idea of your own speed and whereabouts. Doubtless the builders of this Vegan vessel could read this information, but it was an unlearned language to Nelson.

Anxiously he went to the telescreen, turned it on. Nothing appeared but shifting lights. He wanted to turn on a general radio call, but he could not tell how or what controlled that. He tried various plugs at random, giving each a chance. Finally he got a hum on one, called, worked his screen.

■There was a flicker of bright light, the passing glimpse of a face. Holding his breath, he jiggled the button back and forth and then at last the screen steadied and he looked again into the face of a Phobo-sian. The view was not as clear as before, but it was steady.

The stranger saw him, turned away and apparently called. In a few minutes McQueen's ruddy features flashed into view.

"Hi, feller. Heard about your little troubles. What's on your mind?"

Quickly Nelson oudined his problem to McQueen. The man frowned a minute, then said, "Well, I can have the navigators here locate you and give you your speed and direction from our radar observations. You can slow up or speed up a bit and they can follow you and tell you what you're doing. In that way you can build up a rough chart of how your ship operates and what power light indicates what power speed. How's that?"

This made good sense, and although it might mean losing time, it was vital to crack the problem of his ship's controls. McQueen's face gave way to that of Telders, their expedition's crack astral navigator.

Then began a half hour of shifting speed and marking notes. Nelson would push the plug down and dim the bulb. Telders would take a reading on Phobos' super-radar and tell the boy his speed. Nelson would then accelerate slowly and get a new reading from the rocketeer. In this way young Parr finally jotted down a listing equivalent of speed for every power of his control board light and was able to get that clear.

Next he obtained from Telders the exact direction and course that the giant starship was following. They were proceeding at near maximum acceleration (their greatest speed was unsafe in planetary zones) almost directly toward the sun. When they passed within Mercury's orbit, they would shift sufficiently to miss the sun and tear on past it, coming to within eight million miles of its blazing atmosphere. This would be a ticklish and unpleasant experience but it would not last long, so great would be their speed at that moment. Once past it they would blast along away from it and straight toward Earth, slowing down as they got past the orbit of Venus.

The trip would probably take about five weeks at the acceleration of which Phobos was capable. "I advise you to try to catch us and land here," said Telders. "I don't think your little ship could possibly survive such acceleration and such a near-sun course itself."

Nelson nodded. He corrected his direction so that he was following directly on Phobos' trail—having located it on his visual screens by following Telders' directions. Then he pulled out his acceleration plug full blast. The green bulb was blinding.

Suddenly there was nothing else to do but wait. It would take hours to catch up with Phobos and there was nothing to do but sit it out. And now Nelson realized that he hadn't eaten, that he was famished.

He waved good-by to Telders, telling him that he'd tune back in in another hour, and switched off. He set out to find the cube's kitchen.

The ship was indeed a little house! He looked into a couple of small bedrooms, oddly equipped, but clearly sleeping chambers with recognizable pneumatic beds. He passed through a sort of wardroom-library, whose books were small wall panels which flashed rapidly moving series of unreadable colored symbols when activated. There were markings on doors in these symbols, and he recognized that the alphabet these Malakarji used was made up of seven simple symbols, but always used in color, thereby making the same symbol serve at least nine possible letters, depending on whether the figure was red, or blue, or some other color.

He found the kitchen at last, a compact chamber with a counterlike board running the length and the usual plugs, marked with colored letters. It dawned on Nelson then that if the ship had been last used a few thousand years ago, there would be no hope of finding edible supplies!

Well, nothing gained by not trying. He began to work the plugs to see what he could get.

He got water right away. There was a squishing sound and a little transparent container popped out of a wall opening, like a plug from a message tube. He held it in his hand and looked at it. There was a cap at one end which he untwisted, and after that it was just like a glass of water. It tasted odd, tangy, with a curious, but not unpleasant chemical undertone. But it quenched the thirst.

Several other plugs did not work. One disgorged another transparent container filled with a grayish jellylike substance. When he untwisted the cap, it gave off an odor so bad that Nelson gagged. He looked hastily around for a garbage disposal unit, saw an opening in the opposite wall and tossed it in. There was a gulping sound, the opening closed a mechanical jaw, then slid open again, empty and waiting.

After testing all the plugs, he found that there were about five that produced results, not counting the one with the rotten contents. He had an assortment of containers, each filled with some kind of food, not one of which he could recognize, and all seemingly made of brightly colored jellylike materials. He tried one.

It was good, almost meaty in flavor. Hungrily he ate it all, scooping with his fingers, having found no evidence of spoons or forks. He tried one of the others, found it different but equally satisfying—and suddenly he realized that his hunger had gone, that he had fed.

Well, at least he wouldn't starve on this trip, he thought. The food was apparently synthetic, manufactured by heaven alone knows what atomic alchemy from raw materials. Another secret that would be a boon to Earth! He wondered whether the first container, the foul one, was a breakdown on that food line, or whether it was something the builders of the ship actually liked. There were still some people back on Earth who liked such things as whale blubber, rancid butter, Limburger cheese, hundred-year-old eggs, and slugs under rocks, so why not allow the Mala-karji similar peculiarities?

He returned to the central control room, tuned back on Phobos. His father answered this time and they chatted awhile before plugging off. The moon had had enough of a head start so that even at full acceleration it would be a good long time before Nelson could catch up. And now he was getting tired.

So he went to the nearest bedroom, curled up on the Vegan pallet there, and fell asleep. For once he felt at ease and the gravity of the ship gave his body a comfort it had not felt for too long a time.

He woke almost ten hours later, having slept much longer than he'd intended. He sat up refreshed, glanced at his watch, and went into the control room. He could see that Mars had grown appreciably smaller and near-ing his blind underside. He sought again to spot Phobos visually but still failed. Yet it should have been closer. He tuned in and again caught a Phobos observer, who called in McQueen, evidently the only Earthling on duty at that time.

Bryan looked a little worried when he saw Nelson.

"I'm afraid I've got some bad news for you, my boy," he said. "You haven't gotten any closer to us in the past few hours; in fact, you're falling behind."

Nelson bit his lip. "I've been on full acceleration all this time," he said. The other shook his head.

"Yes, but so have we. And, my lad, this moon here is something really terrific. We're going faster than you are and gaining steadily. I guess your ship, and no ship that size, could hope to beat this star-going freighter. But here's your dad."

John Carson Parr came into sight and McQueen stepped aside for him. The older man rubbed his eyes, having just awakened from sleep, and peered anxiously at his son. "I hope you're well set on that old houseboat of yours," he said, trying to be light, "because you're going to have your own private yacht for some time."

Nelson tried to smile, though he felt uneasy at the thought of making the long journey past the sun to Earth by himself. "Oh, I'm okay. You ought to taste the food here—more crazy flavors of gelatin than we ever dreamed of in our wildest nightmares!"

The older Parr cracked a smile. "That's good. Dold-nan can't slow up his moon to pick you up. He's got thousands of other lives to consider. So you'll have to follow us as best you can."

"That's all right. I wouldn't expect Phobos to wait for me. Can you have Telders plot me a course of my own?"

His father nodded. "We've already worked it out. Telders will give you the listings and tell you when to shift speeds and directions. We expect Phobos to reach Earth in about five weeks as you know, by going the shortest, fastest and most dangerous way. However, we've worked out a more circular orbit for you, that won't take you much closer than inside Venus' orbit and have you swing out and join up with Earth in about four months' time. To make it any sooner would be altogether too risky for that little space-going bungalow."

"It looks as if I'll have plenty of time to learn to read their books," Nelson said jokingly.

"Doubt you can do that," said his father, not catching the tone of his son's comment. "However, I suppose you'll find some way to pass the time. I've got to tell you that we may not be able to keep in contact much longer as we outdistance you. Besides, I know Doldnan is worried about our conversations. He thinks the Marauders may be able to spot us by it."

"That's right," said Nelson. "I guess—we'd better say good-by then until we meet on Earth." He smiled at his father, who said some cheery words and stepped aside for Karl Telders.

Nelson jotted down the navigator's readings and thanked him. Getting one more glimpse of his dad, he waved, called farewell, and cut off the telescreen. Nelson was alone in space.

Now began a period of inactivity, of quiet, watchful flight. Nelson carefully kept track of the passage of time, dividing his periods into nights and days, living by the accurate hands of his spaceman's watch. He carefully, systematically, explored all the comers of the houselike cube, teaching himself as much as possible of the value of each and every machine and device in it. He examined the ground floor with its odd drive, but refrained from trying to get to the root of anything there for fear of breakage.

The alphabet and "books" of the Malakarji remained unreadable, though he did spend a day listing the various symbols and their colored variations and trying to decipher them. He caught no evidence anywhere of pictures and never learned just what the Malakarji Vegans looked like.

It was at a time when he was about halfway between Mars and the orbit of Venus when he happened to make a routine check of his control room radar board. Phobos was long off the board and out of sight, probably nearing its destination. Mars was a red disk barely visible toward the rear of a side window. No other objects showed on his board, no asteroids of which he had passed a few, not even meteor clusters which registered briefly as blue sparks.

He saw on the edge of the board, in the direction of Mars, a little yellow dot. Now red was for planetary objects, white for his own ship, blue were meteors, and a wisp of green had appeared once for a small comet. But what did yellow represent?

He watched the dot and even as he watched, a second yellow dot appeared, then a third. He caught his breath, wondered. Then four more yellow dots appeared. The first dot was now visibly closer to his central white square, and as he watched, the others began to fan out behind it like the V of a flight of wild ducks.

travel between them requires an exact knowledge of all the immediate locations, directions and speeds, and the ability to figure out at lightning speed the same relationships at any given time in the future. It was work performed by intricate machines, built into the controls of Earth's ships.

Probably there was such machinery built into the Vegan spaceship too, but Nelson had never located it, and if he had, would not likely have been able to determine how to use it. Furthermore, he lacked the astro-gators' charts which every ship carried giving the figures for the solar system planets.

At this moment there was a difficult decision for him to make—one that he must make without delay. If he tried to outrace the Marauders, it might possibly work, but it would result in his becoming desperately lost, perhaps doomed to chase Earth around the sun by hit-or-miss efforts for years to come—if the cubical space house's mysterious power source held out that long.

Yet not to change speed would mean his capture or destruction for sure. For an instant he hung over the plugs at his odd control table, his hands hanging motionless. For an instant thoughts of Earth ran through his head, of its men and women rushing to prepare defenses, of spaceships being hastily equipped with available weapons to stand off invasion. Every second, every hour, every day gained for them was valuable. The life of one man was nothing. He smashed down on his speed plug, watched the green bulb suddenly flare blindingly as his fingers relentlessy pressed down the plug.

He felt a strain growing on him. In spite of the excellent system of gravity and compensational effects built into the amazing eubeship, it was evident that he was under tremendous acceleration. On his observation dial he saw the flying wedge of yellow dots suddenly pull back, start to disappear off the board, as they were outstripped.

Now their progress off the board stopped as only one was left in sight at the edge of the board. Stubbornly it lingered, refusing to disappear. Then, to Nelson's horror, it slowly, slowly, began to crawl back.

The green speed bulb still blazed, and yet the pursuing ship was coming back and then the second and third yellow dots fought their way back into range and slowly the others began to creep up.

Nelson knew that his die was cast. He was already ahead of Telders' carefully plotted course, at what speed, the unreadable gauges of his Malakarji craft could not tell him. There were no planets near him. He was somewhere near the orbit of Venus, but that body was far away. Nelson punched the controls that would turn the ship, swerve it off.

If he could not outrun his pursuers, he could dodge, twist, turn, give them a chase for their money!

The cube swung far away and the yellow dots swerved off the board again. Now Nelson headed on, at right angles to the course he had been following. He took the time to glance out of the visual window panels, but he could not see the Marauders. He knew he wouldn't, for they must be tens of thousands of miles distant and invisible against the star-strewn blackness of the sky.

He went back to his panel, and again the yellow dots had come into sight, swinging after him, catching up. He watched awhile as they drew closer and closer. He had another idea now.

When he felt that they must be very close, when their V was well into the board, nearing the white square central light that was Nelson's ship, he yanked up the speed plug completely. The green indicator suddenly dimmed and went out. His ship's engines were off.

He felt a vertigo as the little house's gravity vanished with the silencing of the engines. His feet drifted up from the deck and his head reeled as weightlessness returned.

On the panel he saw the yellow dots sweep past his cube fast and vanish off it in the other direction. Nelson punched a direction plug, rammed down his speed again, and the white cube started to reverse its speed, to dash away in another direction.

For a while it seemed to work. Anxiously Nelson hovered over the panel, but the yellow dots continued to be absent. For a moment he thought uneasily that perhaps the Marauders had not been chasing him, had been headed toward Earth, and that he had sacrificed his course needlessly. Perhaps he had only mistakenly supposed they knew of his existence, and had simply misinterpreted their change of direction.

He realized that he was perspiring freely as he watched the board. His ship was probably heading back out toward Mars again if its speed had been fully reversed. He wondered if it was so, because he knew that it would have been impossible for any Earthbuilt rocket to make such a reversal. But the capacities of this cube were unknown.

He supposed that some sort of magnetic lines of force were the guiding means of its propulsion. His father had briefly mentioned something about cosmic power lines of force unknown to terrestrial science, about accumulators, and had ventured the hint that the cubeship's power might be attained in some such way. But the capacities of such a vessel were still unclear, if indeed that was the means.

Well, maybe it had worked. Maybe the Marauders were left behind, but if they were roving the solar system, he'd encounter them again. Nelson realized that he had better investigate the cube's weapons.

There were what seemed to be gun projections on each of the four walls—at least he remembered seeing the little bulges as he had gone into the craft for the first time. He went into die outer shell, saw that there were such bulges at the inside, but that apparently the controls for them were also in the central room. He returned, hunted for them.

He slid aside a metal panel on one wall and saw four small polished disks set therein. He pressed one of the several plugs set neatly beneath each one. Instantly the disk became transparent and he saw that it was a small visual panel giving a view of space similar to that shown by the major "windows." Across this disk appeared various spidery cross lines, directional lines.

Nelson pushed a second plug and a glow appeared in the center of the crossbars. It changed slowly from blue to green as he watched. He heard a humming sound coming from the board. The green changed slowly to yellow and began to work into orange. In a flash of intuition it struck Nelson that a force charge was building up, that something was charging the weapon in that wall.

The orange changed to a burning red dot, and then there was a click, and a plug popped out. The red dot remained, and now Nelson was sure that all he had to do was to push the new plug in and the weapon would discharge.

Taking no chances, young Parr proceeded to activate and charge the other three gunsights. Then he returned to the main control observation panel.

Even as he went toward it he knew the yellow dots were back. He leaned over the panel. The V of nine pursuers was there, reversed, coming again straight as an arrow for Nelson's ship.

He could dodge again, but eventually they would catch him. He decided to try his luck with the ship's guns.

Nelson watched the yellow dots creep slowly closer to his ship. He stepped over to the wall panel and the four visual disks. On one of them a spot of yellow had appeared at one far edge. The first of the Marauders was in sight of the ship's detectors.

Nelson risked a glance out the actual window panel, but he could see nothing against the stars. But the gun-sights showed the enemy moving slowly closer to the central line of crossbars.

Another yellow dot appeared dimly behind the first one, but the first was visibly glowing brighter. Nelson watched closely with held breath as the yellow dot drew nearer the glowing point of scarlet. Minutes passed as he stood, keyed on edge, waiting for the two dots to overlap. At last the red dot began to eclipse the yellow one, to show an orange tint. He watched, his hand on the plug, and then came the moment that there was but a single dot in the exact center of the disk—a bright pure orange. Nelson pushed the plug in.

There was an instantaneous flash of blinding white, and when Nelson's eyes stopped blinking, the disk was dark, one yellow spot—that of the second ship-hovering near the rim, and a dimmed yellow dot rapidly moving out to the edge and vanishing. A spot of blue shone in the crossbars and began to build up to green, as a new charge was loading into the gun.

Evidently the weapons launched a bolt of atomic power, like a huge lightning blast. He wondered whether it had destroyed the Marauder or only disabled it.

Now he glanced at the three other weapon disks and was dismayed to see that two of them carried yellow dots in sight. While he had been waiting, the rest of the pursuers had come up, were surrounding his ship, closing in.

He had not yet tasted the power of their weapons. His shot had probably taken them completely by surprise. But now they would come for him with their weapons blazing. Nelson realized that if they did, he had but scant moments to live.

He gritted his teeth. Well, he'd put up a fight as long as he could. All his four guns were activated, and on two of them, yellow dots were closing in to his target sight. He watched them come, bracing himself unconsciously for the blow that must surely be heading his way.

But somehow they were holding their fire. He was wet with perspiration as another red fire spot turned orange with its target. He slammed down the plug, and was rewarded by another blinding white flash, taking care this time to look away so that his sight would not be dazzled.

But when he looked back the yellow dot was still in the center of the disk and glowing brighter and brighter. He gazed with horror. Somehow the shot had been neutralized, deflected!

There came a terrific clap of thunder in his ears and the cube jolted violently. Nelson was thrown from his feet. The ship's lights dimmed almost to darkness as he slid across the floor, tingling as if a mighty hand had slapped him.

He sat up dazed and shaken. Slowly the ship's lights struggled back into brightness again. Nelson got to his knees, and then to his feet, dizzy from the shock. He shook his head, forced himself back to his full senses, groped back to the defense panel. But all four disks were black, lifeless, burned out.

Somehow, he thought, they were able to catch that thunderbolt, toss it back on its track, back to me! The ship was now helpless!

He hurried back to the control panel, but to his horror, it too was dark. They had blown the ship's control system entirely. He was now boxed up, blind in space, out of control.

Nelson sat down and stared a moment. Would the

Marauders leave him there now, go on their way? No, he decided, it wasn't like them. They'd come in person to look the ship over, to see what they had captured. Well, he'd give them a fight if they did!

He got up, went to the room he'd been using as sleeping quarters, found his spacesuit, climbed into it. He buckled it on fully, secured his space helmet tightly, leaving only the face panel open. Attired thus, he went to the ladderway to the lower level, descended, and found the cabinet of tools that he had discovered there in his tour of exploration. He found a nice thick metal bar, a couple feet long, a perfect crowbar or cudgel. Armed with this, he clambered back up to the central chamber.

He didn't have too long to wait. In a little while he heard a bump and a scraping sound along the outside of the ship. There was a clanging as if something was being affixed to the outside. Then there was a buzzing sound, and he recognized the noise of the outer space lock door being opened. There was a vibration in the floor as heavy feet tramped through and a sudden stir in the ship's air as the inner lock door slid open.

Nelson closed his helmet face panel, slipped up to the entry to his chamber, and hefted his crowbar. He heard the clang of heavy feet stamping around down on the floor below. Then suddenly a black metallic helmet popped up through the round passageway in the floor. Nelson swung at it, and the head pulled back.

He had a glimpse of a curiously ridged black helmet, of a broad eye panel beneath it, and a brief glimpse of two eyes darkly within. At least the Marauders were humanoid, Nelson thought.

Why, Jim was dead, and terrible things had happened, and there had been Kunosh and his lies and treachery and then the cubical ship and then a chase.

The Marauders! The thought exploded in Nelson's head like a bomb. His eyes popped open and he sat up in bed with a start.

He blinked. The first thing he saw was a triangular piece of cloth tacked to the wall bearing the inscription in bright red letters, Solis Lacus General School. It was his old school banner. He swiftly moved his eyes about. There was a carefully hand-framed fix-photo of his father and some ceremony. Against the wall was a jumping stick and other athletic equipment. His eyes fell on his old bureau, on his little folding desk, on a chair. On the chair was a pile of clothes, neatly folded. His rocket-travel jumper, his shoes.

He looked at his bed, and it was his own bed and this was his own room in his father's house on Mars. Nelson rubbed his eyes, looked at his hands. Could this all have been a dream?

But the memory was too vivid. He rubbed his head and winced a little. There was a tender spot on his scalp where the Marauder club had struck him. This was no dream! But how had he got here? And what had happened to the space plunderers?

He climbed out of bed, half expecting someone to rush in, attack him. But he heard nothing. He was dressed in a pair of his own pajamas, a pair he remembered having left behind.

Hastily he changed clothes, got dressed. He glanced at himself in a mirror. He seemed changed, spacetanned. He looked as if he had been through an experience, no doubt about it.

Dressed, he stared around the bedroom he thought he had left behind forever. It seemed unchanged, and yet... he carefully enumerated everything in it. There was a change. Something caught his eye on the main wall. There had always been a blank panel there, a Martian picture panel presumably, inactive like all the Martian mysteries. It was still there—but it was no longer black and dull.

The panel was alive with light and color. Nelson went over, stared at it. There was a picture there, a painting perhaps, if you could imagine a painting made of light and pure color and incredible full-dimensional realism. It showed a scene on some strange fantasy world. Two suns glowed down from a purple sky and a figure in weird armor was battling with a dragonlike being. Nelson stared at it, awed by the scope. It might have been a true color, true depth photo—but it was fantasy.

Or was it fantasy? Perhaps—perhaps it was an actual photo of some place in the universe.

Nelson now perceived that another panel presumed to hide the original closet fixture of the Martian room was gently bright with color, though not picturing anything. He went over to it, touched it, and the panel drew silently aside.

There was a closet there, and in it hung clothing of strange designs and weaves, the clothing of the lost Martians.

Nelson opened the door of his room, went out. He heard nothing, saw nobody. Swiftly he went through the house. Everywhere it was the same. Where there had been mysterious and unresponsive panels, fixtures that wouldn't operate, now there were life and energy. The rooms glowed with a source of light plainly different from the crude string of Earth-made atomic bulbs. The kitchen apparatus, oddly designed, was responsive to the touch. The closets would open and there were all manner of Martian wonders in them.

In the main room, Nelson touched a panel that had been dark as long as he could remember and music came into the room. Music that followed no rules of symphonic construction, yet pleased and charmed. And with the music, lights and colors played over the room in harmony with it.

Nelson now did what so far he had not dared to do. He looked out of a window. It was apparently early morning, for the sun was rising low in the dark sky. Already the Iollipoplike plants that grew everywhere in the city were unfolding their cores, to reach out hungrily for the light that meant life to them. And Nelson realized that there were at least twice as many of these plants as there had been before.

There was a roadway passing the house and he saw something come along it. There was a flash and he got a glimpse of an oddly shaped vehicle bulleting past him ... a Martian "car," one of those glimpsed on radar photos in the hidden vaults but never actually gotten at by Earth's explorers.

He left the window, suddenly hungry, returned to the kitchen. A panel revealed rows and rows of what were probably Martian canned edibles, but Nelson decided not to chance them. There was still his mother's portable storage space and there were still plenty of good old Earth foods left behind. So he made himself a breakfast and as he sat there, he tried to figure things out.

There wasn't much he could work on. He had been caught by the Marauders, overcome. Obviously he had then been taken back to Mars by them, installed here, while they systematically plundered the old planet of its hidden treasures. Evidently they'd had no trouble cracking the secrets of its vaults. Probably to as accomplished a race of superscientific bandits, this would be simple.

Nelson was wondering how long it would take them to loot Mars before they set off to feast on Earth, and what they intended to do with him, when he heard footsteps come up to the door of the house. They were hard, firm steps, and Nelson gulped down the food in his mouth, stood up and went into the living room just as the door opened and two men came in.

They were short and chunkily built, both with the same kind of darkly tanned space-burned complexions, both with sharp pale blue eyes, both with short shocks of red hair, both smiling with reckless confidence. They were the faces of Marauders that Nelson had last seen through the eye slits of black space armor.

Now the two men, wearing brilliantly colored jackets, short leathery pants, and knee boots, stared at Nelson. One laughed, advanced toward the boy. "Ah," he said in jovial-sounding though somewhat sharply clipped words, "here's our bantam rooster now, up and doing."

And before Nelson could get over his surprise, the Marauder grabbed him by an arm and slapped him comradely on the back. The young man jerked his arm away, turned angrily.

"Oh, now, Taktor," called the other man, "watch out! He's liable to give you a dose of his strong right arm too!"

The first man hastily disengaged himself, backed away, holding up his hands, while laughing. "Take it easy," he said quickly. "Whoa, boy, we don't mean any harm!"

The other man nodded, also smiling broadly. "Indeed not. Why, we think you put up a real good batde. I know at least one commander that's not going to live down the wallop your Malakarji bolt handed his ship. He's going to be a mighty foolish-looking officer every time your story comes up!"

Nelson blazed up. "You don't mean any harm! Why did you follow me? Why do you come tearing up and down the universe on mischief? I don't know what you call yourselves, but the rest of the universe calls you a gang of murdering Marauders!"

The first man held up his hands again, shaking his head softly, but still smiling. "Uh—uh, now don't get mad," he said. "We know just what it is that some people have called us. I guess to them we might be the Marauders. But you got us wrong, boy. We're just after a little adventure and fun and exploration. And maybe right a few wrongs while getting them."

"Oh," said Nelson sarcastically, "you call looting and plundering this old planet fun and adventure, do you? And I suppose when you start in to burn and murder on Earth, that'll be called exploration?"

The two men's faces suddenly sobered. The first one shook his head. "Now wait a minute, young fellow, before you go on like that. Better sit down and talk a bit. You've got a lot of strange ideas." He set am example by drawing up a cushion and sitting down.

His comrade switched off the wall music and sat down himself. Nelson, suspicious, settled himself o* a chair.

"First," said one, "I'd better introduce myself. I'm Taktor: Word-leamer, and this is Bodril: Space-leader. We've been given the job of talking this over with you. As you can tell by my name, it's my profession to learn languages and I took the liberty of learning yours when you were unconscious the last few days. We have means of reading brain patterns and transposing them to other brains that can give us the exact hang of a language almost overnight."

Nelson nodded slowly. Then that would account also for their knowledge of where he had lived when on Mars. They'd picked that up in the course of their probing.

"Second," said the man called Bodril, "we're not doing the looting and plundering around here; you and your friends were doing that. This house now. You think of it as yours and you've moved your stuff in here and tried to break open the private closets and belongings of its real owners. This happens to be the home of Kaktal: Valve-maker and his family, and he's had to put off claiming it and coming home until we get things cleared with you.

"To top it off, we hoped to find things as spick and span as we left them and instead we find all sorts of monkeying around. You people tried to blow up our vaults, even tried an atomic blast in one place. You marked up our cities, dumped your furniture all over the place, tried to fool around with our plantations, ran all kinds of crazy wiring all over the place, and so on. It's us that should be angry, not you."

Nelson jumped to his feet. "What are you trying to put over! Already you're trying to steal this planet as your very own, handing out the houses, and taking great airs just because you know how to work the lost Martian vaults and locks. You come from some forgotten hole in the galaxy, tearing about, breaking up honest people's civilizations, and leaving a trail of wreckage. If this world belongs to anybody, it would be the old Martians. And since they're all gone and buried, it's the rightful inheritance of their neighbors in space, and that's us people of Earth!"

The two stared at him for a moment, speechless. Then, as one, they turned, their eyes wrinkled, and burst into fits of laughter. They slapped each other on the back and howled.

Finally Taktor caught his breath, wiped his brow, and choked out to the indignant Nelson, "Why—don't you know yet what we're talking about? The 'forgotten hole in the galaxy' we came from is here, right here! We're the 'lost' Martians, fellow! This is our world! We're from Mars and we've come home!"

"You! You are the real Martians!" Nelson exclaimed in amazement. "But how can that be? Where have you been? We found no sign of you." He stopped, then suddenly narrowed his eyes and added suspiciously, "Or is this just a trick on your part? Are you making a claim just to throw a false track?"

Taktor and Bodril stopped smiling, looked at each other briefly. "Well," said Bodril, "that's a good point. How can we prove we're the rightful owners of this world?"

Taktor waved a hand. "Oh, I think we can prove it all right. Now that our vaults are open, the Martian files available, our young friend will have no trouble seeing the truth. For one thing he'll find the clothing we left in our houses fits our build. He'll find pictures, screen records, life studies, color statues, and so on in our various halls and museums and he'll recognize our people from tiiem. He can study our history for himself.

"Here," he turned to Nelson, "watch this." He turned to the wall panel which had been serving as a music channel, flicked his hand over it. Immediately it cleared, presented a scene looking in upon a room. There were several people there, dressed in odd costumes and evidendy they were engaged in bitter controversy. Nelson recognized that tiiis was undoubtedly part of a play, probably being run off on some entertainment channel.

The costumes were fantastic, definitely of a prema-chine culture, and the play probably represented something from the works of some Martian Shakespeare or an Aristophanes. The locale was undoubtedly Mars, and the characters were clearly of the same race as his two Marauders. All were red-haired, all pale-blue-eyed.

Taktor waved his hand again and the picture was replaced by one recognizable as a classroom platform, whereon an instructor was obviously explaining something about history and pointing to a chart on the wall. This chart, actually a wonderfully alive relief map, was recognizable to Nelson as part of the familiar Martian landscape. Despite his suspicion, he leaned forward with interest, studying what seemed to be the outlines of ancient Martian states, as they must have been in some early pre-canal-building period.

Taktor waved his hand again and again, and more and more scenes of all sorts appeared. Discussions, dances, musicmakers, more plays. Clearly there was a widely varied culture alive on Mars at that moment, a culture whose people were always the race of the Marauders, and which was so deep, so widespread, and so clearly geared to the red planet as to leave the matter no longer disputable.

Nelson nodded to Bodril's arched eyebrows. "You've made your point, I admit it. But that doesn't account for where you've been or how you got your bad reputation as Marauders."

Bodril smiled. "I guess that calls for some history, eh, Taktor?"

The Word-learner nodded soberly. "That's one of the things I'm supposed to go into now, before we can bring this young Earthling before the Command Board. Make yourself comfortable then, and I'll try to clear things up a little."

and our original and oldest currency consisted of pledges and permits for water.

"We had a number of wars among each other as time went on," said Taktor, and his flickering fingers in the air over the wall panel called forth various changes of scenery. There were shots of walled cities, snug amid green cactus jungles, shots of men in bronze and iron armor bashing away at each other with swords and axes. "This sort of thing lasted thousands of years, our states growing in size, our race moving out, discovering other fertile belts, spreading over all the habitable areas always in search of water.

"In the course of this time we improved our civilization—and our ways of warfare. We learned to make self-moving vessels for the land and even for the air. By and by only three big combinations of cities existed as self-ruling states, and there was the grave danger of a new and final war with the newly developed atomic power weapons."

Taktor again displayed a hemisphere of Mars and this time Nelson could note that the deserts had spread, the green areas contracted, the lakes and seas vanished.

"About this time also we ourselves realized that our world had changed even in the course of our own history. We also were noting that our atmosphere was slowly thinning, that our world was growing colder. A great conference was called and our best brains thrashed the whole thing out. We had never become many different races—all Martians are the same color and build, all had the same language, so really there was nothing dividing us save matters of pride and points of government. All these were not important as soon as we realized that no one could win a war wherein the planet itself was dying. We discussed this thing for an entire generation, with every man and woman joining in by means of radio communication, and eventually we emerged with one state federation and with a long and difficult program for saving the planet. We pooled our resources, went without, but in another generation we had laid out the main canal system, set up the system of water supply from our polar reserves, organized our agriculture on a world conservation basis."

Nelson's fascinated eyes saw the familiar network of canals sprout across the face of the hemisphere. He saw thousands of men toiling with atomic and hand diggers to lay down tens of thousands of miles of unbreakable and uncorrosive pipelines. He saw men going through the growing fields and forests destroying the unproductive plants and cultivating only those which produced the most food value at the least water usage.

"Because we saw that air too was thinning, we next set out to build airtight cities, to put our factories and main structures underground," went on Taktor, and scenes illustrating this flashed before Nelson s eyes.

"All this work took time and several thousands of your years went by before we had completed it. By then our world was much as it is today, our agriculture tightly controlled and almost entirely automatic. We had evolved atomic sciences to points which enabled us to make immense caverns, unbreakable walls, to travel where we willed."

"Did you build spaceships then?" asked Nelson.

"You could have gone to Earth then, conquered it for yourself."

"We didn't pay much attention to spaceships in those days, but after our work was completed we did. We visited Earth ..." On the screen flashed a scene taken from a ship approaching Earth. Nelson watched and noticed that it was different from the world he'd known. Great white ice sheets covered much of its Northern Hemisphere and swirling clouds obscured the rest of the planet. Obviously it was a period during one of the great ice ages.

"We found Earth an uninviting world, stormy and cold, filled with jungles such as we had never imagined, wild beasts of terrible temper—for there were never any big animals on Mars, there were no other mammals besides ourselves—and wild savage men." Here Nelson got a glimpse—an actual 3-D color photo taken from fife—of cavemen, hairy, painted, bent-shouldered men, whose sharp eyes peered from shaggy eyebrows, and whose hands clutched crude spears of chipped stone.

"Although Earth had the water and air we needed, we didn't like it, preferred the quiet and order of Mars. We went to all the other worlds of this system, but you must know yourself what we found. None could ever be home, none were inviting."

Taktor flashed a few quick scenes of the planets Nelson himself had studied. "So we settled down on our own world and studied and thought and debated. By and by our various arguments over matters of the most obscure and often silly points of philosophy, of game making, became more and more violent. Fights between debaters became frequent, and struggles between audiences at games and lectures became commonplace. More and more we found ourselves returning to the ways of violence and combat. Instead of the fight for food and water which had marked our early days of savagery, we had fights over athletic contests or differences of opinion as to whether the universe was expanding or contracting. People began to go armed and men wore insignia to demonstrate their particular enthusiasms.

"Finally it reached such a point of bloodshed that we were all a little surprised and frightened." Here there was a scene in an underground arena, obviously one of the caverns beneath a city. A mass of Martians were milling about, and Nelson caught glimpses of knives rising and falling, splashed with red, and finally the incredible blast of a small atomic bomb blotted out the arena.

"We called a planetwide conference and again our whole world took counsel. It became clear to us that we were stagnating, that having no further frontiers to discover, no more great building projects to make, we were turning upon ourselves. Our frustration was breaking us down. We discussed then the problem of finding a way to fly to the stars."

Taktor stopped a moment. Bodril: Space-leader leaned forward, said, "You see the stars are infinite in number. Once we could go to the stars, there could never be an end to exploration, to adventure. And maybe we could find other civilized beings to debate with, to exhaust our energies on, to trade knowledge with."

Bodril sat back, glanced at Taktor. "Sorry to internipt." The other looked at him, said, "Maybe you ought to continue from here. It's more in your line now."

The Space-leader nodded, turned again to Nelson. "Perhaps you Earthlings have considered the problem of star travel?"

"Yes," Nelson answered. "We have thought of it, but it has always seemed a hard and profitless task. The stars are so far away that even if we could travel at the speed of light, 186,000 miles a second, it would take us almost four years just to get to the nearest star. It would take an equally long time to come home. And it will never be possible to travel even at that light speed, because solid matter, such as ships and men, would cease to exist as matter and become merely energy when moving so fast."

Bodril nodded. "I see you people are well advanced. Not at all like the cavemen Taktor showed us. You have hit on the root of the problem exactly.

"With our perfected release of atomic power, it is possible to imagine a spaceship accelerating until it actually becomes light. We knew we could send a ship to the stars if we wanted to. It would be a matter of keeping the spaceship as fast as possible without too dangerous a distortion due to the laws governing mass and speed. The safety point in actual practice turns out to be about half the speed of light. So that we could go to the nearest star and return, not in eight years, but in sixteen years."

Taktor put in, "That is always assuming there was anything worth seeing around the nearest star. And as a matter of fact, there wasn't much." He waved a hand.

On the wall appeared a long black ship, much like the present Marauder craft Nelson saw it leave Mars, head out into the great vastness of space toward a dim star. He saw that star grow into a red ball, Proxima Centauri he supposed it to be from his lessons. Around it he saw one dark huge world appear, a cold gaseous planet deadly to life. He saw the black ship turn, circle awhile, and then head back. He saw it ease down onto Mars and land.

"The men who flew that craft were due for a terrible surprise," said Bodril. "They thought they had found an amazing thing, for once they had started out, their trip had seemed to last but a few short months instead of the long years that they had prepared for. They thought that the theories of astronomy and physics were wrong, that the stars were easily reached in short times. But they returned to find that what had been but a few months to them was still seventeen years for those they had left behind! Their friends were old or dead, their families grown up or changed, their children seeming older than their parents."

"I know," said Nelson. "It was the time distortion that takes place as speed increases. Einstein worked that out on Earth two centuries ago."

"Yes," said Bodril, "then you know. There is a law of nature that rules speed. The faster a body goes, the more its length draws out to infinity and the shorter its time duration becomes. In practice it means that in a spaceship traveling at nearly the speed of light, its actual length is drawn out by this speed to many, many times its original length, and the motion and time sense of passengers and machinery within it is slowed down. To men riding inside, a trip may seem to take but a minute when to those waiting on a home planet the same period takes hours or days. The crew of a starship live and age slowly, but they themselves are not aware of it, for everything about them has changed in the same proportion. Only when they slow down, return to normal, can the difference be discovered."

"What this meant," said Taktor slowly, "was that trips to the stars were perfectly practical within the lifetime of the crew, but that the price they would pay would be permanent exile from their families and homes. The world they would return to after*what might seem a trip of a single year would be a hundred or a thousand years in the future of the world they had left. They would be friendless men on a planet of strangers. It was too high a price to pay."

There was silence for a while in the room. Then Taktor went on, "The matter was discussed for a long time and no one came to any decisions. A few men did leave in ships, and did come back to be lonely strangers. But nobody wanted this fate. For a while the matter was let drop. Then the violent fights and arguments began again and new bloodshed was breaking out. Again, the whole world took counsel."

Another presentation of people in Martian homes listening to their scientists and social leaders talking. "This time a startling new course was proposed. At first it was so unusual, people were unable to credit it as serious. But then it began to take hold on imaginations and very rapidly became the rage of every man, woman, and child on Mars.

"It was nothing less than the mass vacationing of the entire population to the stars! The idea was to build enough ships, thousands in number, to have a place for every living Martian, including the children and babies. Then to seal all fragile things, to lock up our cities and properties, to install automatic controls on the agriculture and workings of our world, and go en masse to the stars! In that way we could all have our relaxations, end our frustrations, enjoy the glories and wonders of the universe, visit distant worlds, learn new things, and all return home together. There would be no lonely exiles, no agonized young men looking for familiar faces amid a world of their great-grandchildren grown up, no wives or mothers kissing their men good-by forever, knowing they would never see them again during their lifetime."

Nelson watched the screen as he saw the project go into operation. He saw the great fleets of black star-ships growing, as the incredible underground factories of Mars poured them out from materials mined on asteroids and planet cores. He saw the controls being set up, he saw the sealing up of the caverns and vaults by impermeable subatomic shields. At a question as to why these shields resisted even the atom bombs of the Earth explorers, Taktor said, "Actually a dimensional shift was used here. A thin layer of matter on the surface of each vault wall and door was shifted slightly out of this dimension, warped across a fourth dimension flex. No blast could even touch such a surface."

Finally Nelson saw a scene whereon the great black starships, each holding thousands of people, lifted from their desert beds and took off for the stars.

"That first star trip took seven years for those on the ships. We visited dozens of stars, explored hundreds of planets, turned up several that were inhabited. After our seven years we returned to a Mars that had aged several thousand years. But it did not matter, for we had done our work well. The planet was still ready and waiting, our fields still growing, our water still pumping, our homes still untouched.

"That first trip satisfied our frustrations and culture for almost ten generations. We had brought back so much in knowledge and material that it took that length of time to exhaust it all. The tenth generation took off again for the stars, and again Mars was left untenanted and locked up."

Nelson watched fascinated as scenes among the stars flashed before him. He saw worlds galore, some vast and cold, some small and dark. He saw mountainous worlds and desert ones. He saw red suns and blue suns and multiple ones. He saw beings of dreadful shape attack the Martians when they landed. He saw manlike beings welcome the star visitors, trading with them, saw the Martian men and women wandering the streets of weird cities arm in arm like tourists on vacation. He saw Martians climbing mountains so high their tops were without air. He saw Martians hunting incredible beasts in purple forests. And he saw warfare.

He saw that the Martians were a tough and vigorous people, who responded to attack with attack. That they never flinched from opposition but met it and forced their way in. He saw that they never took no for an answer from a strange civilization, insisting always on their right to entry. Nelson was not sure he could agree with their actions.

"No wonder they called you Marauders," Nelson said. "It seems to me that you did a lot of things no honest explorer would do."

"Hey, wait before you call us names," said Bodril. "But we weren't really pirates. We stole notlung, we enslaved nobody, we left things always better and richer than we found them."

"What about the Vegans?" asked Nelson, thinking he had found a flaw in their story. "They are terrified of you, told about your reputation in their system, and how they had to flee from your coming."

"Oh, them," said Bodril. "They're a pretty slippery crowd. They lived on a small mountainous world and used to try to wreck approaching spaceships from the civilized planets near them—like the Malakarji, one of whose ships you seem to have been using. When a ship would land on their world in need of fuel or repair, they'd trap the crew, steal the ship. They had a completely wrong and crooked system of thinking. They pretended they were better than their neighbors and didn't want to trade with them when actually it was their neighbor worlds who cut them off, refused to take chances with their sneaky cunning."

"We gave them a shaking upl" said Taktor. "Scared the daylights out of them. Their leaders, the worst ones, built a couple of big spherical starships, and ran away when they heard we were coming. Don't know where they went, but without those leaders we were able to open their world to honest trade and make it safe for space travelers."

"That happened on this last trip," said Bodril. "I myself helped on that campaign. Only a couple years

say one of the moon ships simply ran away, but the other headed for Earth along with your father and his men. Do you suppose your peoples will believe them?"

When Nelson nodded, he went on, "If that is so, then Earth must be expecting us to attack them in force. Then your people must be arming themselves and getting ready to beat off any visitors from Mars! And if these Vegans live up to their word and hand over some of their power sources, then the situation is quite dangerous."

He fell silent, but Bodril took up the line of thought. "You see, Nelson, it is one thing to develop tremendous power sources, power beyond the atom, power that taps the basic core of the universe itself such as we have done and the Vegans have, and to know just what it is that you are doing. As you discover it, you learn its terrible possibilities. Wrongly used, or used by people who don't really understand it, you can blow up a planet by accident. You can explode a sun! The trouble is that the Vegans were too cowardly to play too much with it and that your Earth people are still too young to be properly cautious. Add to that their idea that they are defending themselves against Marauders and total ruin, and they may not wait to learn."

Nelson saw their point. "And you can't wait and let them be, because then they'll get up an attacking expedition and come here. Earth won't stand still. We're like yourselves, you know."

Taktor: Word-learner smiled a bit. "You know why? You know why we never attempted to interfere or attack the men of Earth and why we don't want to have to fight them off now? It's because we're all from the same stock. We Martians are your own distant cousins. We have the same inheritance."

"What!" Nelson said, startled. "How's that?"

Taktor nodded. "One of the reasons that led us into hunting around the universe is to find the race that took our ancestors from Earth. It must have been about a half million terrestrial years ago when something or some star-beings were passing through the Sol System. They landed on Earth, captured a group of shaggy cavemen, took them to Mars, and dumped them in the middle of the largest and most fruitful jungle area in the Southern Hemisphere. Those were our ancestors.

"We found this out by exhaustive archaeology. We can trace primitive skeletons back just so far and no farther. And when we first visited Earth we proved our theory completely. So, you see, we are as human as you are. We, too, developed fast, a little ahead of you in some ways, mainly because Mars never had the ice ages, earthquakes, floods and epidemics that your much larger world had, not to mention the problem of different races and languages."

Bodril glanced at a timepiece. "I think we can break this up. Personally, I'm hungry. How about something to eat?"

They got up and went into the kitchen. There Taktor manipulated the native cooking equipment, incredible working devices, and with hardly any effort the three sat down to a rather remarkable meal the like of which Nelson had never eaten before.

When they were done, Taktor informed them that they were expected at a meeting of the Command Board where the matter of Earth would be discussed.

Nelson climbed into his warm outdoor jumper, adjusted his respirator, and went out of the house. The two Martians hadn't brought along respirators, and the reason for that was that their vehicle was parked just outside. They didn't bother about the short time they were in the open, simply leaped into their vessel and when Nelson was in, slammed the airtight door and went. The vehicle, a simple eggshell device, had almost no machinery and skimmed the ground without actually touching it. The power supply was a system of broadcast power used throughout Mars. This had been shut down and sealed during the Martians' absence and was another reason for the utter failure of the colonizers to make any native equipment function.

The Command Board was located in a large domed building at the center of the city. Several vehicles were already there, and Nelson and his two escorts entered to find a group of about thirty men already seated in comfortable easy chairs around a series of low tables obviously housing recorders and transmitters.

There was a strong similarity between all the men there, Nelson noted as he was introduced and presented to several of the leaders. None were over five feet four, all were very broad-shouldered and deep-chested, stocky and muscular, and all were red-haired.

A graying oldster seemed to be the head. He was Norfal: World-talker and played the role of chairman.

When Nelson had seated himself, Bodril took the floor. Talking in Martian, he outlined Nelson's story and the entire problem. Sitting next to young Parr, Taktor: Word-learner whispered a rapid translation of everything that was going on.

Then there followed some heated discussion. There was none, Nelson was relieved to note, who counseled war. It was agreed that every effort must be spent to find some way of making peace with their neighbor world. The problem was how to get through to them.

A suggestion was made that they broadcast directly to Earth when their planetary positions permitted it. If Nelson came before the cameras and explained, then perhaps that would break down terrestrial suspicions.

"It won't work," Nelson said when he heard this. "I am sure the Earth leaders will believe that I am speaking under hypnosis or compulsion. That sort of trick was tried in our wars and they would surely suspect it. I don't think they would believe anything you said, in view of the stories the Vegans must have told them."

Another suggestion was made that they simply leave Earth alone. But Norfal himself rejected that. If they did, then sooner or later Earth would attack the Martians. Even if they didn't, if ever a future generation of Martians wanted to set off for the stars again, leaving Mars untenanted, they would certainly find the planet devastated or ruined by the time they returned. It was essential, Norfal insisted, to make peace and establish good relations right away, without delay.

Finally Nelson took the floor. He had been listening to all the various viewpoints and saw that they were getting nowhere. "I have an idea," he said. "I think I can find a way." Taktor was translating his words into Martian as he spoke.

"While the people of the Earth will not believe me if I spoke from Mars, they will believe me if I meet them in person. It seems to me that I have got to go back myself and tell them about you. If you still have the Vegan cubeship you found me in, I can go back in that, for they must be still expecting it. They would let me through if I arrived in that."

There was some conversation and then Norfal answered: "I think you speak correctly. If you yourself could appear there, then indeed they might listen to reason. But it will not be possible for you to use the cubeship. Not only would it be all too slow in making the trip, but it is still out of commission. The blast that hit it has burned out its powerlines. They would all have to be repaired. And then, if you appeared in that ship, why would they believe you? There would be no evidence that your account of the—the Marauders—was anything but a dream."

Bodril got the floor. "I think I can find a solution. If Nelson Parr could go back to Earth in a Martian cruiser, he would arrive there very fast and very soon. The cruiser would prove our reality. While perhaps a whole fleet of our ships might run the risk of encountering terrestrial suicide attackers, one swift small cruiser could slip through their guards . . . and would not be such a menace as to draw too heavy or too violent fire."

This struck a responsive note. The meeting ended with the plan's approval. Besides its being the quickest way out, Nelson realized that the bravado and daring involved in the cruiser idea appealed to the Martian sense of adventurousness.

During the next few days Nelson had a chance to look over the secrets of the world on which he had been born. He was shown through the great underground workshops, saw the vast all-mechanical machinery that turned out most of the products used on Mars without the need of human supervision. He spent fascinating hours in museum and recording rooms, gazing with awe and wonder at the vivid records of life on distant star worlds. All too soon the time came to depart.

The cruiser was a sleek black craft, a couple of hundred feet long, streamlined and rakish in appearance. It rested on the desert floor outside Solis Lacus, in an area reserved to the great star vessels themselves. For as far as the eye could see were row on row of giant ships, thousands of feet in length, towering up like manmade cliffs. Among them the cruiser seemed almost a speck.

Bodril: Space-leader, who had been a captain of one of the great ships, had volunteered to pilot the little cruiser to Earth. Once again Nelson took leave of the red desert of Mars as he paused in the lock of the cruiser to look back. Then he entered, found his way to the forward control cabin.

Bodril was seated at an amazingly simple control board. It was a glassy hemisphere in which seemed to float tiny images of the inner planets. The board was strictly automatic. All controls were primarily machine run. The art of space flight had been so simplified that all a pilot had to do was to indicate where he wanted to go. The mechanical controls did the rest, automatically computing the course, launching the ship, directing its speed and slowing it on arrival.

Without more ado, Bodril flicked the starter and leaned back. The ship left the ground, soared upward

outside torpedo tubes could be rigged on their hulls easily enough, fitted with rocket torpedoes adopted from the guided missiles used during Earth's last great war. With atomic warheads, they could be quite dangerous. Add proximity fuses, and it wouldn't be much trouble firing them at an invader."

Bodril nodded. "That sounds like a good guess. I've got our outer radar screens up so if anything approaches us, we'll know of it."

They could see the Earth defender approaching now and beginning to show up in their telescopic view-plates. It was, as surmised, a small streamlined rocket, heading still directly toward them, riding on streams of blue-white atomic fire from its tubes. Now, even as they watched, they saw a spurt of yellow-white fire from its side and a spark seemed to travel out from it and vanish.

"That's the torpedo!" said Nelson. Bodril nodded silently, shifted a lever on his panel. Instantly a point of color appeared in the hemispheric space sector plate. The torpedo was on track. Bodril watched it a moment, saw it nearing the thin outer circle that marked their own ship's outer sphere of sensitivity. The moment it touched, there was a flicker, then a flash.

For an instant Nelson was blinded by the glare that swept in through the nearest visual port in the control room. "That was a thorium disintegration bomb," said Bodril.

"Won't the rays penetrate our hull even now?" asked Nelson.

"Nothing but visual light can get through our neu-tralizer screen," said Bodril. "A good thing too. If I thought it was otherwise, Fd have blown that cruiser off the map the instant we spotted it. We used to do that when attacked, until we got the Procyon people's neutralizer devices."

"We should make a careful point not to hurt anyone," said Nelson. "We've got to dodge and box, but if any of the defenders get killed, it will be very hard to keep Earth tempers down."

"I know," said Bodril. "We'd be the same. You just better hope then that that cruiser was shielded against its own bomb's blast and rays too."

The cruiser was already slipping out of sight, far off and losing speed. Nelson expressed the opinion that its crew surely must have been armored against the danger. "Probably had but the one torpedo," he added.

Now again they were heading on toward the great glowing green-and-blue world. Nelson could see the aura of its atmosphere glowing in the rays of the sun. He could see mists veiling parts of its surface, and the lower edge of South America peeking through. It was a beautiful world, he thought, the finest in the system.

The moon was not in their path, but was just emerging from the other, farther, side of Earth. A good thing, Nelson thought, for the bulk of whatever war fleet Earth had equipped was probably based there. He explained this thought to Bodril.

"That's luck," said the Martian space leader. "Maybe we can beat them in."

On they sped, cutting down the miles to Earth hundreds by the second. Again their radar signaled trouble. There was a line of little spheres somewhere up ahead of them. Even as they watched they saw these mysterious objects beginning to float in their direction.

"Must be space buoys of some sort," said Nelson. "Patterned after the floating mines of the sea wars. They'll be dangerous."

"Manned?" asked Bodril, but Nelson shook his head and explained the idea of mines to him. The Martian broke into a smile. "Well, as long as they're not manned, they're no trouble."

He whistled into the ship's communicator. Several answering hails showed his gunners alert. One after another the Martian cruiser's various gun turrets blinked into activity on the central board's markers. One after another the little spheres vanished from their vision screen.

"What's happening?" asked Nelson.

"I'm giving my gunners some target practice. They're picking off the space mines by hand beam," was the reply.

Another alarm bell rang. This time there were several ships rocketing into their field of vision from behind them.

"Clever," said Bodril. "They slipped up behind us from somewhere. That'll keep us alert, but probably won't be much trouble. As long as we outdistance them. Besides, we can play a little trick on them that'll have them puzzled." He pressed several buttons on his board, grinning.

"The one thing they probably don t expect is that we plan to land on Earth," said Nelson.

"Exactly. I'm sure they think we are just an advance scout for a great fleet of invaders. So I'm giving them plenty of grounds for their belief." He looked up from the board. "Look to our rear, Nelson," he said.

The young Terrestrial turned, went over to the port plate that looked out their rear. He gasped. Stringing out behind them was a long line of identical cruisers, long black Martian craft. Farther behind them, behind even the pursuing Earth ships, was a shadowy black cloud, the mighty bulk of the entire Mars Marauder fleet!

"What is it! Where'd they come from!" For one terrible sinking instant the thought flashed through Nelson's head that he had been deceived. That the Martians had fooled him into revealing Earth's secrets and then had secretly launched a Marauder invasion on his heels. Bodrii's chuckle relieved the thought in an instant.

"Nice show, eh! It's a three-dimension picture show we're putting on. For the last million miles we have been spraying out a special type of dust on our course. Projectors from our rear are now setting up some excellent films of our fleet in full array. The dust motes pick up the projection, which is atomically attuned to them and reflect the picture perfectly. It also will deceive radars. But look at our attackers!"

On their viewplate, the Earth fleet was shifting swiftly, spreading out, moving no longer directly for the advance Martian ship, which appeared to be but the smallest and weakest of patrol scouts, but was heading suicidally for what appeared to be the mighty mass of battleships a million miles to their rear!

"There isn't a single defender coming for us now!" said Nelson amazed. "How could they be so foolish!"

"Don't take it to heart," said Bodril. "After all, these men are truly brave, believe me. There are mighty few races in the galaxy that would have the courage to go for the main fleet when surprised like that. Almost all simply cut and run. You realize that every man in those Earth ships believes he is going to certain death? That every man there is prepared to throw away his life in an effort to save his world? It makes even a man like myself proud to share ancestors with them."

A lump came to Nelson's throat. What the Martian had said was true. Those ships must have been hastily manned with volunteers from the trade crews, from passenger ships, from mining craft. They must have been piloted by every navigator his world could scrape up, down to and including first-year students at Nelson's own academy. For now it was clear that the trick had lured away all Earth's defending spaceships.

From the direction of Luna, another fleet was emerging, an array of some thirty or forty ships of all sizes. This new and last fleet was also heading out, away from Bodril's little cruiser, out to meet what they thought was the invincible horde of Marauders!

But the cruiser was already within the moon's orbit and slowing down, beginning to work itself into an orbit preparatory to making a landing. "Look!" Nelson pointed.

A tiny sphere was showing its small crescent now between the moon and Earth. "It's Phobos!" Nelson said. "That's the Vegan starship that used to be one of Mars* moons. It seems to have been placed in an orbit around Earth now, a sort of halfway station for the moon flight." Bodril nodded quiedy, asked about any other satellites. Nelson named the several man-made platforms that circled the Earth closer down, and Bodril recorded the information for their caution in coming in.

"Where will we land?" he asked. "Better make it some place where they won't try to bomb us from the air. I suggest a big city."

Nelson looked over the face of the Earth which now filled their entire view. "If we land in a city, they wouldn't dare try to drop an H-bomb from the air warplanes. That's a good idea. In fact I know the best place for our landing. Why not the central courtyard of the Capital's official buildings? That's the last place they'd dare to risk even bullets!"

"Good," said Bodril, "point it out to me."

Nelson did so. "Can this ship land in such a limited space?"

"Watch and see," was the reply.

The rakish black Martian craft swooped down. In an instant the whistling of the outer atmosphere vibrated through their hull. Lower and lower the piratical vessel plunged, the land below jumping up toward them in green vividness. Now they were tearing along over roads and houses, swooping ever closer to the great towered city that was their goal. Past outskirts and suburban homes, over city streets, over skyscrapers and factories, their ship whooshed.

Below, Nelson could see the flickering dots of aircraft futilely trying to pursue them. Blazing red jets plunged up at them, and little clouds of smoke gave evidence of the way in which ancient cannon and antiaircraft protections had been taken from warehouses and museums and installed around the metropolis.

The attacks stopped as the craft was over the city itself. The danger of damaging buildings and citizens was too great to risk for the one attacker.

Now ahead could be seen the slender white towers and graceful domes of the Capital itself. Bodril swept his ship up, stood it almost on its tail, and then began to slip it down in ever narrowing spirals.

Nelson hung onto the handgrips and watched. He saw the tops of the towers appear, and noticed them dotted with the faces of watching people. Gracefully the ship slipped below the roof levels, spiraled down past windows clogged with the staring government clerks and employees. Then the central courtyard appeared, a wide plaza lined with trees and gardens, with statues of great men of history ornamenting the outer lanes.

With the ease of a dancer, the black cruiser from Mars righted itself and settled without a jar in the exact center of the marble plaza.

Bodril turned in his seat, waved a hand. "It's up to you now, Nelson," he said.

Walking with the tremor of the seaman first come to land, of the spaceman unfamiliar to gravity, and with the son come home, Nelson made his way to an opening airlock, past the sober-faced squat crew members watching him silently, down the lock and stepped out on the surface of Earth.

He saw a group of men emerge from the ornate doorway of the great Central Building. Nelson waved to them, started to walk slowly toward them. The men came on hesitantly, then one of them suddenly waved back, ran forward from the group. It was a gray-haired man, a man space-tanned, his face deep-lined. It was John Carson Parr.

The rest of the story is easily told. Once father and son had greeted each other, it was possible to bring Nelson's story before Earth's leaders, with the entire population of the planet following his words on television and radio as he stood before the officials and told them of their Martian neighbors. Bodril appeared later and managed to impress the people of Earth with the humanness of their red planet cousins.

The pact that was negotiated then and there cemented forever the alliance of the only two civilized worlds in this system. That day was a day of rejoicing, a holiday forever.

As for the Vegans, one of their stories is simply accounted for. Doldnan and his Phobosians had already thrown in their lot with Earth, foresworn the ways of their remote ancestors. Their people were given space on the newly cleared and warmed Antarctic Continent, and the secrets of their civilization and science given in exchange for their new home world. The moon ship once known as Phobos remained where it was, a convenient way station for interplanetary flight, an auxiliary moon.

As for the cowardly people of Deimos, Kunosh and his crew, they have never been traced and never been