Happy Thurbelow finished sweeping the long barracks and leaned wearily on his broom. That is, he didn't lean on it, or it would have collapsed him to the floor, but he made the gesture. Why, he wondered, didn't the Masters make the Toughs sweep their own barracks? Perhaps the Toughs couldn't be made, or perhaps the Masters did it just from an excess of cruelty.

Happy's monstrously bloated body sagged, and his skin felt dangerously dry and tight. Happy was so adipose that his hands engulfed the broom handle like a toothpick; under the transparent skin, his flesh was clear and translucent, and there could be seen the tiny red lines of the branching veins. Happy was like a jellyfish, in huge human form.

"Shadow!" he called in a high, grating voice. "I'm going below."

Shadow appeared disconcertingly, ten feet away. Dark-skinned Shadow looked at him silently with white-rimmed eyes. Then Shadow turned and disappeared, as only Shadow could.

Hanging up the broom, Happy waddled to the iron-barred gate that prevented entrance to a downward-plunging ramp. He pressed a button beside it and waited.

He looked out the window beside the gate. The sands of the Desert of Candor stretched orange and bleak under the bronze sky. Somewhere out there to the south, across those sands, under that sky, lay the shining dome of Ophir.

The window would be easily broken, and it was large enough for even Happy's bulky body to pass through. But the oxygen-scant air of Mars would sear his lungs to quick death without a helmet; and even if it would not, Happy's skin would dry and crack in a few hours of that outside air, and he would die in slower agony.

"What is the purpose of your call?" asked an impersonal voice from the loudspeaker beside the barred gate.

"I have finished my task, Master," said Happy, puffing a little. "I seek your grace to go below."

The loudspeaker said no more, but after a moment the gate stirred and lifted into the ceiling. Happy went through it gratefully, and waddled down the gently sloping ramp. The gate descended behind him.

Happy did not know whether Shadow had come through the open gate with him, but it didn't matter. Shadow could slip easily through the bars when he wished.

At the foot of the ramp was a vast, low cavern, stretching out of sight in all directions. It was dim, shading into the darkness of distance. Its floor was water, flat water, subdivided into large rectangular vats. In most of the vats vegetation grew in various stages, greening under the ultraviolet rays that radiated from the low roof. Between the vats ran straight, narrow walkways of packed earth.

Happy waddled along one of the walkways until he found an empty vat. He lowered himself over its edge and sank happily into the still, cool water, like a hippopotamus submerging. He immersed himself completely, then lay back in the water, with only his face floating barely above the surface.

Shadow appeared, apparently out of nowhere, and sat down on the edge of the vat, letting his flat legs dangle into the water.

"Nothing like it," proclaimed Happy, splashing a little. "Nothing on Mars like it. You ought to come on in, Shadow. As flat as you are, you ought to float on the surface without any trouble at all."

Shadow nodded silently, but made no move.

"I don't see why the Toughs can't take care of their own barracks," complained Happy, returning to the subject closest to his displeasure. "You reckon the Toughs are actually the rebels, and the Masters can't make them do anything?"

Shadow shook his head, but whether in negation or disclaimer of knowledge, Happy could not interpret.

Happy flinched, and shifted in the vat.

"There's still part of a skeleton in here," he announced. "I thought this was an empty one."

Moving, he flinched again. With purpose, he aroused himself and ploughed to the edge of the vat.

"I've got to find another vat," he said. "I can't take a nap if I'm going to get punched in the fanny with bones every five minutes."

He heaved himself over the edge onto the walkway with difficulty, and got slowly to his feet. Shadow lifted his feet out of the vat, stood up and vanished.

Happy knew how Shadow was able to disappear so suddenly, and it did not disturb him. Seen directly from front or rear, Shadow had the dimensions of a normal, black-skinned man. But Shadow was flat, no thicker than half an inch. When Shadow turned sidewise, he vanished to the sight.

Occasionally, Happy wondered how Shadow happened to be, and why he was here in the caverns, but it was not the sort of thing to bother his mind for very long.

Happy moved along the walkways, peering into the vats which appeared to be empty. He assumed Shadow was following him; Shadow always did.

Around corners, he came upon blubbery creatures like himself, tending the plants. They nodded greeting at him, and Happy nodded back.

His search was discouraging. All the vats not filled with plants seemed to have corpses in them, in varying stages of decomposition.

Around one corner, Happy came upon a Tough, lounging in the walkway. The Tough was a compact, muscular youth, with bullet head, sullen eyes and hard mouth. He looked as though he lounged with hands in pockets, but, like Happy and all the others, he was naked, so that was just an impression.

Happy stopped. He and his soft kind avoided the Toughs when they could. The Tough looked at him with disinterested eyes, then looked away.

Happy was uncertain what to do or say. His impulse was to turn and go back, but he did not quite dare.

"Are you a rebel, Tough?" he burbled the first thing in his mind, for lack of something else to say.

The Tough looked at him contemptuously. Then, suddenly, the Tough's hard eyes flared with savage excitement and he moved swiftly on Happy. As he began to turn in panic, Happy saw from the corner of his eye another Tough racing around the corner of the walkway to come upon him from behind.

The Tough in front of him reached him and began pummeling him viciously with his fists, the hard fists sinking like painful hammers deep into Happy's flesh with every blow. Happy bleated in fright and distress, trying ineffectually to ward off his attacker.

Then, out of nowhere, Shadow flashed in like a lightning bolt on the other Tough as he had almost reached Happy. There was a brief, squalling tangle and the Tough pitched headlong into a plant-choked vat.

Shadow vanished and reappeared, intermittently, like a flashing light. The first Tough, seeing what had happened to his cohort, ceased pummeling Happy abruptly and took to his heels. He vanished around a corner.

The vanquished Tough climbed out of the vat, sputtering and cursing, and fled in the other direction.

"Oh, my! Oh, my!" exclaimed Happy to the now-invisible Shadow. "What wicked creatures!"

Sore and shaken, he moved on down the walkway, his search now intensified by the need for wetness to soothe his injured flesh.

He came upon a vat without vegetation and, at first joyous glance, thought it empty. Then, disappointment, a comparatively fresh body floated in it, just under the surface.

It was the body of a man. Naked, it was smooth and plump with the water that had seeped into its tissues, and it was a uniform dead-white all over, like the belly of a fish. The face and lips were monochrome white, the hair was bleached, and when it opened its eyes, they were so colorless that the action was almost unnoticeable.

Realizing, Happy was paralyzed with shock.

The dead creature's eyes moved from side to side, then stopped, fixing on Happy. Its chest began to rise and fall slowly, with breathing—under water.

"Shadow!" squeaked Happy helplessly.

Shadow appeared beside him.

"Shadow, it's alive," whispered Happy, desperately frightened.

The two stood side by side, staring breathlessly down into the water. The creature in the vat moved its hands tentatively, it opened its mouth and closed it. Then it stirred with purpose, turned and climbed up over the side of the vat, dripping like a weird creature from the depths of the sea.

It stood up before them, dripping.

The man bent slightly and belched forth a great quantity of water from his lungs. He straightened, and breathed in the air in great, satisfied gasps.

"I'm Dark Kensington," he said in a rusty voice. "Where is this?"

At his words, Shadow disappeared.

Dark Kensington. Had Maya seen him now, she could not possibly have recognized him. The muscular body and dark, handsome face were bloated and pale. The black hair was bleached to pale seaweed, and the blue eyes were completely colorless now.

"This is the Canfell Hydroponic Farm," answered Happy, gaining a little courage. "Under the surface of the Desert of Candor."

"The Desert of Candor?" repeated Dark, and the pale lips twisted in a smile. "They hauled me quite a way. I was at Solis Lacus."

"How did you get here?" asked Happy with sudden eagerness. "Only dead people are thrown in the vats, to make chemicals for the plants. How could you stay alive under water?"

"I imagine I can breathe water for the same reason I can still live after a heat beam burned my guts out, but I don't know what that reason is. I imagine that the first step in finding out is to get out of this place."

"You can't get away from here," said Happy positively. "Nobody ever has."

"We'll see," said Dark confidently. "I gather you and your companion are some sort of prisoners."

"Slaves," corrected Happy with unaccustomed bitterness. "The Jellies are slaves, to work in the vats. I don't know if the Toughs are slaves, too, but the Masters let them sleep in barracks on the surface. Shadow's not either a Jelly or a Tough, and I don't know if he's a slave. Shadow's just Shadow."

"Before you go on," interrupted Dark, "I seem to be extraordinarily hungry."

Happy twittered and quivered. He moved hurriedly around a corner to one of the storage vats, and returned in a moment with a supply of the tasteless gelatin that was their food here. Dark fell to greedily, and Happy, his tongue loosed by this new companionship, started feeding him information in a steady stream.

"I don't know how they get us here," said Happy. "We aren't born here, but something happens to our memories. We can't stay up in the dry air very long, or our skin cracks and our flesh collapses. You see, our tissues are mostly water.

"Everybody down here's like me. Everybody but the Toughs. You'll see them. I don't know how they got here, either, or what use they are. They don't work like we do.

"And Shadow. He's different. Shadow likes me. He stays with me all the time. And then there's Old Beard. He hides down here, and I don't think the Masters know he's here. He's very old and very wise."

"Who are the Masters?" asked Dark curiously, between mouthfuls. "And what sort of work do you do for them?"

"They're the people who run the hydroponic farm. They're normal men, like you—I mean, like you would be if you weren't swollen up and pale like the bodies that are thrown in the vats.

"Old Beard knows; he's very wise. He calls the Masters 'Marscorp.' I don't know why, but it seems that before I lost my memory I knew a language where corp meant body. Like corpse, you know. Maybe it has something to do with the bodies they put in the vats.

"Old Beard says that the Masters are developing Martian foods that we can eat without dying, and he must be right, because sometimes they bring down some hard foods and make some of us eat them instead of gelatin. But those who eat the hard foods always die, so I don't suppose they've succeeded yet, except some of the Toughs. Some of the Toughs have eaten the hard food without dying, sometimes, but they got pretty sick. And then—"

"Hold on! Wait a minute!" exclaimed Dark, holding up a restraining hand. "I know what Marscorp is, and I'm not surprised they're behind it. But I'm trying to digest all this you're throwing at me."

Happy fell silent, reluctantly, and Dark cogitated deeply.

Happy fidgeted, anxious to speak but afraid to interrupt Dark's thoughts.

And then Shadow reappeared. Shadow appeared out of nowhere, and made gestures at Happy. Happy glanced at Dark, timidly. At last, he gained courage to speak.

"Shadow tells me—" he began, then cringed when Dark looked up in surprise. Dark gestured to him to go on.

"Shadow tells me," said Happy, "that Old Beard wants to see you. Will you go with us to Old Beard?"

"Certainly," agreed Dark. "From what you tell me, I'm rather anxious to meet Old Beard, too."

He followed Happy and the alternately visible and invisible Shadow along the paths that twisted among the vats for some distance. At last they ducked into some luxuriant foliage that hung over to form a bower above the space between two vats.

Old Beard sat there, in a corner of the dimness, pale eyes fixed silently on the trio. Old Beard was not so very old. He appeared to be in robust middle age, although his skin was very pale from long existence underground. His hair and heavy beard were long and untrimmed, and were a deep iron-gray.

"Thank you for coming," said Old Beard in a deep, resonant voice that bespoke strength and bore an undertone of bitter determination. "It is safer for me not to move around too much in the open except at certain hours."

"I was glad to come, because I'm sure you can help me and I may be able to help you, too," said Dark. "I'm Dark Kensington."

"So Shadow told me. I find this extremely interesting."

"You've heard of me, then?" asked Dark.

Old Beard laughed, deeply.

"More interesting than that," he said. "Once, before I was marooned here and Happy's people came to know me as Old Beard, I had a name of my own."

He stroked his beard, and favored Dark with a shrewd look from his pale eyes.

"Yes," said Old Beard, "I've heard of Dark Kensington, and there never was but one Dark Kensington, as far as I knew. That's why I find it so interesting. You see, I'm Dark Kensington!"

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