Ross, absorbed in the scene before him, was not prepared for the sudden and complete darkness which blotted out not only the action but the light in his own room as well.

"What—?" His startled voice rang loudly in his ears, too loudly, for all sound had been wiped out with the light. The faint swish of the ventilating system, of which he had not been actively aware until it had disappeared, was also missing. A trace of the same panic he had known in the cockpit of the atomjet tingled along his nerves. But this time he could meet the unknown with action.

Ross slowly moved through the dark, his hands outstretched before him to ward off contact with the wall. He was determined that somehow he would discover the hidden door, escape from this dark cell....

There! His palm struck flat against a smooth surface. He swept out his hand—and suddenly it passed over emptiness. Ross explored by touch. There was a door and now it was open. For a moment he hesitated, upset by a nagging little fear that if he stepped through he would be out on the hillside with the wolves.

"That's stupid!" Again he spoke aloud. And, just because he did feel uneasy, he moved. All the frustrations of the past hours built up in him a raging desire to do something—anything—just so long as it was what he wanted to do and not at another's orders.

Nevertheless, Ross continued to move slowly, for the space beyond that open door was as deep and dark a pit as the room he left. To squeeze along one wall, using an outstretched arm as a guide, was the best procedure, he decided.

A few feet farther on, his shoulder slipped from the surface and he half tumbled into another open door. But there was the wall again, and he clung to it thankfully. Another door ... Ross paused, trying to catch some faint sound, the slightest hint that he was not alone in this blindman's maze. But without even air currents to stir it, the blackness itself took on a thick solidity which encased him as a congealing jelly.

The wall ended. Ross kept his left hand on it, flailed out with his right, and felt his nails scrape across another surface. The space separating the two surfaces was wider than any doorway. Was it a cross-corridor? He was about to make a wider arm sweep when he heard a sound. He was not alone.

Ross went back to the wall, flattening himself against it, trying to control the volume of his own breathing in order to catch the slightest whisper of the other noise. He discovered that lack of sight can confuse the ear. He could not identify those clicks, the wisp of fluttering sound that might be air displaced by the opening of another door.

Finally, he detected something moving at floor level. Someone or something must be creeping, not walking, toward him. Ross pushed back around the corner. It never occurred to him to challenge that crawler. There was an element of danger in this strange encounter in the dark; it was not meant to be a meeting between fellow explorers.

The sound of crawling was not steady. There were long pauses, and Ross became convinced that each rest was punctuated by heavy breathing as if the crawler was finding progress a great and exhausting effort. He fought the picture that persisted in his imagination—that of a wolf snuffling along the blacked-out hall. Caution suggested a quick retreat, but Ross's urge to rebellion held him where he was, crouching, straining to see what crept toward him.

Suddenly there was a blinding flare of light, and Ross's hands went to cover his dazzled eyes. And he heard a despairing, choked exclamation from near to floor level. The same steady light that normally filled hall and room was bright again. Ross found himself standing at the juncture of two corridors—momentarily, he was absurdly pleased that he had deduced that correctly—and the crawler—?

A man—at least the figure was a two-legged, two-armed body reasonably human in outline—was lying several yards away. But the body was so wrapped in bandages and the head so totally muffled, that it lacked all identity. For that reason it was the more startling.

One of the mittened hands moved slightly, raising the body from the ground so it could squirm forward an inch or so. Before Ross could move, a man came running into the corridor from the far end. Murdock recognized Major Kelgarries. He wet his lips as the major went down on his knees beside the creature on the floor.

"Hardy! Hardy!" That voice, which carried the snap of command whenever it was addressed to Ross, was now warmly human. "Hardy, man!" The major's hands were on the bandaged body, lifting it, easing the head and shoulders back against his arm. "It's all right, Hardy. You're back—safe. This is the base, Hardy." He spoke slowly, soothingly, with the steadiness one would use to comfort a frightened child.

Those mittened paws which had beat feebly into the air fell onto the bandage-wreathed chest. "Back—safe—" The voice from behind the face mask was a rusty croak.

"Back, safe," the major assured him.

"Dark—dark all around again—" protested the croak.

"Just a power failure, man. Everything's all right now. We'll get you into bed."

The mitten pawed again until it touched Kelgarries' arm; then it flexed a little as if the hand under it was trying to grip.

"Safe—?"

"You bet you are!" The major's tone carried firm reassurance. Now Kelgarries looked up at Ross as if he knew the other had been there all the time.

"Murdock, get down to the end room. Call Dr. Farrell!"

"Yes, sir!" The "sir" came so automatically that Ross had already reached the end room before he realized he had used it.

Nobody explained matters to Ross Murdock. The bandaged Hardy was claimed by the doctor and two attendants and carried away, the major walking beside the stretcher, still holding one of the mittened hands in his. Ross hesitated, sure he was not supposed to follow, but not ready either to explore farther or return to his own room. The sight of Hardy, whoever he might be, had radically changed Ross's conception of the project he had too speedily volunteered to join.

That what they did here was important, Ross had never doubted. That it was dangerous, he had early suspected. But his awareness had been an abstract concept of danger, not connected with such concrete evidence as Hardy crawling through the dark. From the first, Ross had nursed vague plans for escape; now he knew he must get out of this place lest he end up a twin for Hardy.

"Murdock?"

Having heard no warning sound from behind, Ross whirled, ready to use his fists, his only weapons. But he did not face the major, or any of the other taciturn men he knew held positions of authority. The newcomer's brown skin was startling against the neutral shade of the walls. His hair and brows were only a few shades darker; but the general sameness of color was relieved by the vivid blue of his eyes.

Expressionless, the dark stranger stood quietly, his arms hanging loosely by his sides, studying Ross, as if the younger man was some problem he had been assigned to solve. When he spoke, his voice was a monotone lacking any modulation of feeling.

"I am Ashe." He introduced himself baldly; he might have been saying "This is a table and that is a chair."

Ross's quick temper took spark from the other's indifference. "All right—so you're Ashe!" He strove to make a challenge of it. "And what is that supposed to mean?"

But the other did not rise to the bait. He shrugged. "For the time being we have been partnered——"

"Partnered for what?" demanded Ross, controlling his temper.

"We work in pairs here. The machine sorts us ..." he answered briefly and consulted his wrist watch. "Mess call soon."

Ashe had already turned away, and Ross could not stand the other's lack of interest. While Murdock refused to ask questions of the major or any others on that side of the fence, surely he could get some information from a fellow "volunteer."

"What is this place, anyway?" he asked.

The other glanced back over his shoulder. "Operation Retrograde."

Ross swallowed his anger. "Okay, but what do they do here? Listen, I just saw a fellow who'd been banged up as if he'd been in a concrete mixer, creeping along this hall. What sort of work do they do here? And what do we have to do?"

To his amazement Ashe smiled, at least his lips quirked faintly. "Hardy got under your skin, eh? Well, we have our percentage of failures. They are as few as it's humanly possible to make, and they give us every advantage that can be worked out for us——"

"Failures at what?"

"Operation Retrograde."

Somewhere down the hall a buzzer gave a muted whirr.

"That's mess call. And I'm hungry, even if you're not." Ashe walked away as if Ross Murdock had ceased to exist.

But Ross Murdock did exist, and to him that was an important fact. As he trailed along behind Ashe he determined that he was going to continue to exist, in one piece and unharmed, Operation Retrograde or no Operation Retrograde. And he was going to pry a few enlightening answers out of somebody very soon.

To his surprise he found Ashe waiting for him at the door of a room from which came the sound of voices and a subdued clatter of trays and tableware.

"Not many in tonight," Ashe commented in a take-it-or-leave-it tone. "It's been a busy week."

The room was rather sparsely occupied. Five tables were empty, while the men gathered at the remaining two. Ross counted ten men, either already eating or coming back from a serving hatch with well-filled trays. All of them were dressed in slacks, shirt, and moccasins like himself—the outfit seemed to be a sort of undress uniform—and six of them were ordinary in physical appearance. The other four differed so radically that Ross could barely conceal his amazement.

Since their fellows accepted them without comment, Ross silently stole glances at them as he waited behind Ashe for a tray. One pair were clearly Oriental; they were small, lean men with thin brackets of long black mustache on either side of their mobile mouths. Yet he had caught a word or two of their conversation, and they spoke his own language with the facility of the native born. In addition to the mustaches, each wore a blue tattoo mark on the forehead and others of the same design on the backs of their agile hands.

The second duo were even more fantastic. The color of their flaxen hair was normal, but they wore it in braids long enough to swing across their powerful shoulders, a fashion unlike any Ross had ever seen. Yet any suggestion of effeminacy certainly did not survive beyond the first glance at their ruggedly masculine features.

"Gordon!" One of the braided giants swung halfway around from the table to halt Ashe as he came down the aisle with his tray. "When did you get back? And where is Sanford?"

One of the Orientals laid down the spoon with which he had been vigorously stirring his coffee and asked with real concern, "Another loss?"

Ashe shook his head. "Just reassignment. Sandy's holding down Outpost Gog and doing well." He grinned and his face came to life with an expression of impish humor Ross would not have believed possible. "He'll end up with a million or two if he doesn't watch out. He takes to trade as if he were born with a beaker in his fist."

The Oriental laughed and then glanced at Ross. "Your new partner, Ashe?"

Some of the animation disappeared from Ashe's brown face; he was noncommittal again. "Temporary assignment. This is Murdock." The introduction was flat enough to daunt Ross. "Hodaki, Feng," he indicated the two Easterners with a nod as he put down his tray. "Jansen, Van Wyke." That accounted for the blonds.

"Ashe!" A man arose at the other table and came to stand beside theirs. Thin, with a dark, narrow face and restless eyes, he was much younger than the others, younger and not so well controlled. He might answer questions if there was something in it for him, Ross decided, and filed the thought away.

"Well, Kurt?" Ashe's recognition was as dampening as it could be, and Ross's estimation of the younger man went up a fraction when the snub appeared to have no effect upon him.

"Did you hear about Hardy?"

Feng looked as if he were about to speak, and Van Wyke frowned. Ashe made a deliberate process of chewing and swallowing before he replied. "Naturally." His tone reduced whatever had happened to Hardy to a matter-of-fact proceeding far removed from Kurt's implied melodrama.

"He's smashed up ... kaput...." Kurt's accent, slight in the beginning, was thickening. "Tortured...."

Ashe regarded him levelly. "You aren't on Hardy's run, are you?"

Still Kurt refused to be quashed. "Of course, I'm not! You know the run I am in training for. But that is not saying that such can not happen as well on my run, or yours, or yours!" He pointed a stabbing finger at Feng and then at the blond men.

"You can fall out of bed and break your neck, too, if your number comes up that way," observed Jansen. "Go cry on Millaird's shoulder if it hurts you that much. You were told the score at your briefing. You know why you were picked...."

Ross caught a faint glance aimed at him by Ashe. He was still totally in the dark, but he would not try to pry any information from this crowd. Maybe part of their training was this hush-hush business. He would wait and see, until he could get Kurt aside and do a little pumping. Meanwhile he ate stolidly and tried to cover up his interest in the conversation.

"Then you are going to keep on saying 'Yes, sir,' 'No, sir,' to every order here——?"

Hodaki slammed his tattooed hand on the table. "Why this foolishness, Kurt? You well know how and why we are picked for runs. Hardy had the deck stacked against him through no fault of the project. That has happened before; it will happen again——"

"Which is what I have been saying! Do you wish it to happen to you? Pretty games those tribesmen on your run play with their prisoners, do they not?"

"Oh, shut up!" Jansen got to his feet. Since he loomed at least five inches above Kurt and probably could have broken him in two over one massive knee, his order was one to be considered. "If you have any complaints, go make them to Millaird. And, little man"—he poked a massive forefinger into Kurt's chest—"wait until you make that first run of yours before you sound off so loudly. No one is sent out without every ounce of preparation he can take. But we can't set up luck in advance, and Hardy was unlucky. That's that. We got him back, and that was lucky for him. He'd be the first to tell you so." He stretched. "I'm for a game—Ashe? Hodaki?"

"Always so energetic," murmured Ashe, but he nodded as did the small Oriental.

Feng smiled at Ross. "Always these three try to beat each other, and so far all the contests are draws. But we hope ... yes, we have hopes...."

So Ross had no chance to speak to Kurt. Instead, he was drawn into the knot of men who, having finished their meal, entered a small arena with a half circle of spectator seats at one side and a space for contestants at the other. What followed absorbed Ross as completely as the earlier scene of the wolf killing. This too was a fight, but not a physical struggle. All three contenders were not only unlike in body, but as Ross speedily came to understand, they were also unlike in their mental approach to any problem.

They seated themselves crosslegged at the three points of a triangle. Then Ashe looked from the tall blond to the small Oriental. "Territory?" he asked crisply.

"Inland plains!" That came almost in chorus, and each man, looking at his opponent, began to laugh.

Ashe himself chuckled. "Trying to be smart tonight, boys?" he inquired. "All right, plains it is."

He brought his hand down on the floor before him, and to Ross's astonishment the area around the players darkened and the floor became a stretch of miniature countryside. Grassy plains rippled under the wind of a fair day.

"Red!"

"Blue!"

"Yellow!"

The choices came quickly from the dusk masking the players. And upon those orders points of the designated color came into being as small lights.

"Red—caravan!" Ross recognized Jansen's boom.

"Blue—raiders!" Hodaki's choice was only an instant behind.

"Yellow—unknown factor."

Ross was sure that sigh came from Jansen. "Is the unknown factor a natural phenomenon?"

"No—tribe on the march."

"Ah!" Hodaki was considering that. Ross could picture his shrug.

The game began. Ross had heard of chess, of war games played with miniature armies or ships, of games on paper which demand from the players a quick wit and a trained memory. This game, however, was all those combined, and more. As his imagination came to life the moving points of light were transformed into the raiders, the merchants' caravan, the tribe on the march. There was ingenious deployment, a battle, a retreat, a small victory here, to be followed by a bigger defeat there. The game might have gone on for hours. The men about him muttered, taking sides and arguing heatedly in voices low enough not to drown out the moves called by the players. Ross was thrilled when the red traders avoided a very cleverly laid ambush, and indignant when the tribe was forced to withdraw or the caravan lost points. It was the most fascinating game he had ever seen, and he realized that the three men ordering those moves were all masters of strategy. Their respective skills checkmated each other so equally that an outright win was far away.

Then Jansen laughed, and the red line of the caravan gathered in a tight knot. "Camped at a spring," he announced, "but with plenty of sentries out." Red sparks showed briefly beyond that center core. "And they'll have to stay there for all of me. We could keep this up till doomsday, and nobody would crack."

"No"—Hodaki contradicted him—"someday one of you will make a little mistake and then——"

"And then whatever bully boys you're running will clobber us?" asked Jansen. "That'll be the day! Anyway, truce for now."

"Granted!"

The lights of the arena went on and the plains vanished into a dark, tiled floor. "Any time you want a return engagement it'll be fine with me," said Ashe, getting up.

Jansen grinned. "Put that off for a month or so, Gordon. We push into time tomorrow. Take care of yourselves, you two. I don't want to have to break in another set of players when I come back."

Ross, finding it difficult to shake off the illusion which had held him entranced, felt a slight touch on his shoulder and glanced up. Kurt stood behind him, apparently intent upon Jansen and Hodaki as they argued over some point of the game.

"See you tonight." The boy's lips hardly moved, a trick Ross knew from his own past. Yes, he would see Kurt tonight, or whenever he could. He was going to learn what it was this odd company seemed determined to keep as their own private secret.