It did not stop disturbing him. It was a matter that grew in his mind as the days of preparation sped by. It interposed itself between him and Twissell; then between him and Noys. When the day of departure came, he was only distantly aware of the fact.

It was all he could do to rouse a shadow of interest when Twissell returned from a session with the Council subcommittee. He said, "How did it go?"

Twissell said wearily, "It wasn't exactly the most pleasant conversation I've ever had."

Harlan was almost willing to let it go at that, but he broke his moment's silence with a muttered "I suppose you said nothing about--"

"No, no," was the testy response. "I said nothing about the girl or about your part in the misdirection of Cooper. It was an unfortunate error, a mechanical failure. I took full responsibility."

Harlan's conscience, burdened as it was, could find room for a twinge. He said, "That won't affect you well."

"What can they do? They must wait for the correction to be made before they can touch me. If we fail, we're all beyond help or harm. If we succeed, success itself will probably protect me. And if it doesn't--" The old man shrugged. "I plan to retire from active participation in Eternity's affairs thereafter anyway." But he fumbled his cigarette and disposed of it before it was half burned away.

He sighed. "I would rather not have brought them into this at all, but there would have been no way, otherwise, of using the special kettle for further trips past the downwhen terminus."

Harlan turned away. His thoughts moved around and about the same channels that had been occupied to the increasing exclusion of all else for days. He heard Twissell's further remark dimly, but it was only at its repetition that he said with a start, "Pardon me?"

"I say, is your woman ready, boy? Does she understand what she's to do?"

"She's ready. I've told her everything."

"How did she take it?"

"What?... Oh, yes, uh, as I expected her to. She's not afraid."

"It's less than three physiohours now."

"I know."

That was all for the moment, and Harlan was left alone with his thoughts and a sickening realization of what he must do.

With the kettle loading done and the controls adjusted Harlan and Noys appeared in a final change of costume, approximating that of an unurbanized area of the early 20th.

Noyshad modified Harlan's suggestion for her wardrobe, according to some instinctive feeling she claimed women had when it came to matters of clothing and aesthetics. She chose thoughtfully from pictures in the advertisements of the appropriated volumes of the news magazine and had minutely scrutinized items imported from a dozen different Centuries.

Occasionally she would say to Harlan, "What do you think?"

He would shrug. "If it's instinctive knowledge, I'll leave it to you."

"That's a bad sign, Andrew," she said, with a lightness that did not quite ring true. "You're too pliable. What's the matter, anyway? You're just not yourself. You haven't been for days."

"I'm all right," Harlan said in a monotone.

Twissell's first sight of them in the role of natives of the 20th elicited a feeble attempt at jocularity. "Father Time," he said, "what ugly costumes in the Primitive, and yet how it fails to hide your beauty, my-my dear."

Noys smiled warmly at him, and Harlan, standing there impassively silent, was forced to admit that Twissell's rust-choked vein of gallantry had something of truth in it. Noys's clothing encompassed her without accentuating her as clothing should. Her make-up was confined to unimaginative dabs of color on lips and cheeks and an ugly rearrangement of the eyebrow line. Her lovely hair (this had been the worst of it) had been cut ruthlessly. Yet she was beautiful.

Harlan himself was already growing accustomed to his own uncomfortable belt, the tightness of fit under armpits and in the crotch and the mousy lack of color about his rough-textured clothing. Wearing strange costumes to suit a Century was an old story to him.

Twissell was saying, "Now what I really wanted to do was to install hand controls inside the kettle, as we discussed, but there isn't any way, apparently. The engineers simply must have a source of power large enough to handle temporal displacement and that isn't available outside Eternity. Temporal tension while occupying the Primitive is all that can be managed. However, we have a return lever."

He led them into the kettle, picking his way among the piled supplies, and pointed out the obtruding finger of metal that now marred the smooth inner wall of the kettle.

"It amounts to the installation of a simple switch," he said. "Instead of returning automatically to Eternity, the kettle will remain in the Primitive indefinitely. Once the lever is plunged home, however, you will return. There will then be the matter of the second and, I hope, final trip-"

"A second trip?" asked Noys at once.

Harlan said, "I haven't explained that. Look, this first trip is intended merely to fix the time of Cooper's arrival precisely. We don't know how long a Time-lapse exists between his arrival and the placing of the advertisement. We'll reach him by the post-office box, and learn, if possible, the exact minute of his arrival, or as close as we can, anyway. We can then return to that moment plus fifteen minutes to allow for the kettle to have left Cooper-"

Twissell interposed, "Couldn't have the kettle in the same place at the same time in two different physiotimes, you know," and tried to smile.

Noys seemed to absorb it. "I see," she said, not too definitely.

Twissell said to Noys, "Picking up Cooper at the time of his arrival will reverse all micro-changes. The A-bomb advertisement will disappear again and Cooper will know only that the kettle, having disappeared as we told him it would, had unexpectedly appeared again. He will not know that he was in the wrong Century and he will not be told. We will tell him that there was some vital instruction we had forgotten to give him (we'll have to manufacture some) and we can only hope that he will regard the matter as so unimportant that he won't mention being sent back twice when he writes his memoir."

Noys lifted her plucked eyebrows. "It's very complicated."

"Yes. Unfortunately." He rubbed his hands together and looked at the others as though nursing an inner doubt. Then he straightened, produced a fresh cigarette, and even managed a certain jauntiness as he said, "And now, boy, good luck." Twissell touched hands briefly with Harlan, nodded to Noys, and stepped out of the kettle.

"Are we leaving now?" asked Noys of Harlan when they were alone.

"In a few minutes," said Harlan.

He glanced sideways at Noys. She was looking up at him, smiling, unfrightened. Momentarily his own spirits responded to that. But that was emotion, not reason, he counciled himself; instinct, not thought. He looked away.

The trip was nothing, or almost nothing; no different from an ordinary kettle ride. Midway there was a kind of internal jar that might have been the downwhen terminus and might have been purely psychosomatic. It was barely noticeable.

And then they were in the Primitive and they stepped into a craggy, lonely world brightened by the splendor of an afternoon sun. There was a soft wind with a chilly edge to it and, most of all, silence.

The bare rocks were tumbled and mighty, colored into dull rainbows by compounds of iron, copper, and chromium. The grandeur of the manless and all but lifeless surroundings dwarfed and shriveled Harlan. Eternity, which did not belong to the world of matter, had no sun and none but imported air. His memories of his own homewhen were dim. His Observations in the various Centuries had dealt with men and their cities. He had never experienced this.

Noys touched his elbow.

"Andrew! I'm cold."

He turned to her with a start.

She said, "Hadn't we better set up the Radiant?"

He said, "Yes. In Cooper's cavern."

"Do you know where it is?"

"It's right here," he said shortly.

He had no doubt of that. The memoir had located it and first Cooper, now he, had been pin-pointed back to it.

He had not doubted precision pin-pointing in Time-travel since his Cubhood days. He remembered himself then, facing Educator Yarrow seriously, saying, "But Earth moves about the Sun, and the Sun moves about the Galactic Center and the Galaxy moves too. If you started from some point on Earth, and move downwhen a hundred years, you'll be in empty space, because it will take a hundred years for Earth to reach that point." (Those were the days when he still referred to a Century as a "hundred years.")

And Educator Yarrow had snapped back, "You don't separate Time from space. Moving through Time, you share Earth's motions. Or do you believe that a bird flying through the air whiffs out into space because the Earth is hurrying around the Sun at eighteen miles a second and vanishes from under the creature?"

Arguing from analogy is risky, but Harlan obtained more rigorous proof in later days and, now, after a scarcely precedented trip into the Primitive, he could turn confidently and feel no surprise at finding the opening precisely where he had been told it would be.

He moved the camouflage of loose rubble and rock to one side and entered.

He probed the darkness within, using the white beam of his flash almost like a scalpel. He scoured the walls, ceiling, floor, every inch.

Noys, remaining close behind him, whispered, "What are you looking for?"

He said, "Something. Anything,"

He found his something, anything, at the very rear of the cave in the shape of a flattish stone covering greenish sheets like a paperweight.

Harlan threw the stone aside and flipped the sheets past one thumb.

"What are they?" asked Noys.

"Bank notes. Medium of exchange. Money."

"Did you know they were there?"

"I knew nothing. I just hoped."

It was only a matter of using Twissell's reverse logic, of calculating cause from effect. Eternity existed, so Cooper must be making correct decisions too. In assuming the advertisement would pull Harlan into the correct Time, the cave was an obvious additional means of communication.

Yet this was almost better than he had dared hope. More than once during the preparations for his trip into the Primitive, Harlan had thought that making his way into a town with nothing but bullion in his possession would result in suspicion and delay.

Cooper had managed, to be sure, but Cooper had had time. Harlan hefted the sheaf of bills. And he must have used time to accumulate this much. He had done well, the youngster, marvelously well.

And the circle was closing!

The supplies had been moved into the cave, in the increasingly ruddy glow of the westering sun. The kettle had been covered by a diffuse reflecting film which would hide it from any but the closest of prying eyes, and Harlan had a blaster to take care of those, if need be. The Radiant was set up in the cave and the flash was wedged into a crevice, so that they had heat and light.

Outside it was a chill March night.

Noys stared thoughtfully into the smooth paraboloid interior of the Radiant as it slowly rotated. She said, "Andrew, what are your plans?"

"Tomorrow morning," he said, "I'll leave for the nearest town. I know where it is-or should be." (He changed it back to "is" in his mind. There would be no trouble. Twissell's logic again.)

"I'll come with you, won't I?"

He shook his head. "You can't speak the language, for one thing, and the trip will be difficult enough for one to negotiate."

Noys looked strangely archaic in her short hair and the sudden anger in her eyes made Harlan look away uneasily.

She said, "I'm no fool, Andrew. You scarcely speak to me. You don't look at me. What is it? Is your homewhen morality taking hold? Do you feel you have betrayed Eternity and are you blaming me for that? Do you feel I have corrupted you? What is it?"

He said, "You don't know what I feel."

She said, "Then describe it. You might as well. You'll never have a chance as good as this one. Do you feel love? For me? You couldn't or you wouldn't be using me as a scapegoat. Why did you bring me here? Tell me. Why not have left me in Eternity since you have no use for me here and since it seems you can hardly bear the sight of me?"

Harlan muttered, "There's danger."

"Oh, come now."

"It's more than danger. It's a nightmare. Computer Twissell's nightmare," said Harlan. "It was during our last panicky flash upwhen into the Hidden Centuries that he told me of thoughts he had had concerning those Centuries. He speculated on the possibility of evolved varieties of man, new species, supermen perhaps, hiding in the far upwhen, cutting themselves off from our interference, plotting to end our tamperings with Reality. He thought it was they who built the barrier across the 100,000th. Then we found you, and Computer Twissell abandoned his nightmare. He decided there had never been a barrier. He returned to the more immediate problem of salvaging Eternity.

"But I, you see, had been infected by his nightmare. I had experienced the barrier, so I knew it existed. No Eternal had built it, for Twissell said such a thing was theoretically impossible. Maybe Eternity's theories didn't go far enough. The barrier was there. Someone had built it. Or something.

"Of course," he went on thoughtfully, "Twissell was wrong in some ways. He felt that man must evolve, but that's not so. Paleontology is not one of the sciences that interest Eternals, but it interested the late Primitives, so I picked up a bit of it myself. I know this much: species evolve only to meet the pressures of new environments. In a stable environment, a species may remain unchanged for millions of Centuries. Primitive man evolved rapidly because his environment was a harsh and changing one. Once, however, mankind learned to create his own environment, he created a pleasant and stable one, so he just naturally stopped evolving."

"I don't know what you're talking about," said Noys, sounding not the least mollified, "and you're not saying anything about us, which is what I want to talk about."

Harlan managed to remain outwardly unmoved. He said, "Now why the barrier at the 100,000th? What purpose did it serve? You weren't harmed. What other meaning could it have? I asked myself: What happened because of its presence that would not have happened had it been absent?"

He paused, looking at his clumsy and heavy boots of natural leather. It occurred to him that he could add to his comfort by removing them for the night, but not now, not now...

He said, "There was only one answer to that question. The existence of that barrier sent me raving back downwhen to get a neuronic whip, to assault Finge. It fired me to the thought of risking Eternity to get you back and smashing Eternity when I thought I had failed. Do you see?"

Noys stared at him with a mixture of horror and disbelief. "Do you mean the people in the upwhen wanted you to do all that? They planned it?"

"Yes. Don't look at me like that. Yes! And don't you see how it makes everything different? As long as I acted on my own, for reasons of my own, I'll take all the consequences, material and spiritual. But to be fooled into it, to be tricked into it, by people handling and manipulating my emotions as though I were a Computaplex on which it was only necessary to insert the properly perforated foils-"

Harlan realized suddenly that he was shouting and stopped abruptly. He let a few moments pass, then said, "That is impossible to take. I've got to undo what I was marionetted into doing. And when I undo it, I will be able to rest again."

And he would-perhaps. He could feel the coming of an impersonal triumph, dissociated from the personal tragedy which lay behind and ahead. The circle was closing!

Noys's hand reached out uncertainly as though to take his own rigid, unyielding one.

Harlan drew away, avoided her sympathy. He said, "It had all been arranged. My meeting with you. Everything. My emotional make-up had been analyzed. Obviously. Action and response. Push this button and the man will do that. Push that button and he will do this."

Harlan was speaking with difficulty, out of the depths of shame. He shook his head, trying to shake the horror of it away as a dog would water, then went on. "One thing I didn't understand at first. How did I come to guess that Cooper was to be sent back into the Primitive? It was a most unlikely thing to guess. I had no basis. Twissell didn't understand it. More than once he wondered how I could have done it with so little understanding of mathematics.

"Yet I had. The first time was that-that night. You were asleep, but I wasn't. I had the feeling then that there was something I must remember; some remark, some thought, something that I had caught sight of in the excitement and exhilaration of the evening. When I thought long, the whole significance of Cooper sprang into my mind, and along with it the thought entered my mind that I was in a position to destroy Eternity. Later I checked through histories of mathematics, but it was unnecessary really. I already knew. I was certain of it. How? How?"

Noys stared at him intently. She didn't try to touch him now. "Do you mean the men of the Hidden Centuries arranged that, too? They put it all in your mind, then maneuvered you properly?"

"Yes. Yes. Nor are they done. There is still work for them to do. The circle may be closing, but it is not yet closed."

"How can they do anything now? They're not here with us."

"No?" He said the word in so hollow a voice that Noys paled.

"Invisible superthings?" she whispered.

"Not superthings. Not invisible. I told you man would not evolve while he controlled his own environment. The people of the Hidden Centuries are Homo sapiens. Ordinary people."

"Then they're certainly not here."

Harlan said sadly, "You're here, Noys."

"Yes. And you. And no one else."

"You and I," agreed Harlan. "No one else. A woman of the Hidden Centuries and I... Don't act any more, Noys. Please."

She stared at him with horror. "What are you saying, Andrew?"

"What I must say. What were you saying that evening, when you gave me the peppermint drink? You were talking to me. Your soft voice-soft words... I heard nothing, not consciously, but I remember your delicate voice whispering. About what? The downwhen journey of Cooper; the Samson-smash of Eternity. Am I right?"

Noys said, "I don't even know what Samson-smash means."

"You can guess very accurately, Noys. Tell me, when did you enter the 482nd? Whom did you replace? Or did you just-squeeze in. I had your Life-Plot worked out by an expert in the 2456th. In the new Reality, you had no existence at all. No analogue. Strange for such a small Change, but not impossible. And then the Life-Plotter said one thing which I heard with my ears but not with my mind. Strange that I should remember it. Perhaps even then, something clanged in my mind, but I was too full of-you to listen. He said: '_with the combination of factors you handed me, I don't quite see how she fit in the old Reality_.'

"He was right. You didn't fit in. You were an invader from the far upwhen, manipulating me and Finge, too, to suit yourself."

Noys said urgently, "Andrew--"

"It all fit in, if I had the eyes to look. A book-film in your house entitled _Social and Economic History_. It surprised me when first I saw it. You needed it, didn't you, to teach you how best to be a woman of the Century. Another item. Our first trip into the Hidden Centuries, remember? _You_ stopped the kettle at the 111,394th. You stopped it with finesse, without fumbling. Where did you learn to control a kettle? If you were what you seemed to be, that would have been your first trip in a kettle. Why the 111,394th, anyway? Was it your homewhen?"

She said softly, "Why did you bring me to the Primitive, Andrew?"

He shouted suddenly, "To protect Eternity. I could not tell what damage you might do there. Here, you are helpless, because I know you. Admit that all I say is true! Admit it!"

He rose in a paroxysm of wrath, arm upraised. She did not flinch. She was utterly calm. She might have been modeled out of warm, beautiful wax. Harlan did not complete his motion.

He said, "Admit it!"

She said, "Are you so uncertain, after all your deductions? What will it matter to you whether I admit it or not."

Harlan felt the wildness mount. "Admit it, anyway, so that I need feel no pain at all. None at all."

"Pain?"

"Because I have a blaster, Noys, and it is my intention to kill you."