Harlan would not have thought that Twissell could have said anything at that moment that could have surprised him. He was wrong.

He said, "Mallansohn. He-"

Twissell, having smoked his cigarette to a stub, produced another and said, "Yes, Mallansohn. Do you want a quick summary of Mallansohn's life? Here it is. He was born in the 78th, spent some time in Eternity, and died in the 24th."

Twissell's small hand placed itself lightly on Harlan's elbow and his gnomish face broke into a wrinkled extension of his usual smile. "But come, boy, physiotime passes even for us and we are not completely masters of ourselves this day. Won't you come with me to my office?"

He led the way and Harlan followed, not entirely aware of the opening doors and the moving ramps.

He was relating the new information to his own problem and plan of action. With the passing of the first moment of disorientation his resolution returned. After all, how did this change things except to make his own importance to Eternity still more crucial, his value higher, his demands more sure to be met, Noys more certain to be bartered back to him.

Noys!

Father Time, they must not harm her! She seemed the only real part of his life. All Eternity beside was only a filmy fantasy, and not a worth-while one, either.

When he found himself in Computer Twissell's office, he could not clearly recall how it had come about that he had passed from the dining area here. Though he looked about and tried to make the office grow real by sheer force of the mass of its contents, it still seemed but another part of a dream that had outlived its usefulness.

Twissell's office was a clean, long room of porcelain asepsis. One wall of the office was crowded from floor to ceiling and wall to distant wall with the computing micro-units which, together, made up the largest privately operated Computaplex in Eternity and, indeed, one of the largest altogether. The opposite wall was crammed with reference films. Between the two what was left of the room was scarcely more than a corridor, broken by a desk, two chairs, recording and projecting equipment, and an unusual object the like of which Harlan was not familiar with and which did not reveal its use until Twissell flicked the remnants of a cigarette into it.

It flashed noiselessly and Twissell, in his usual prestidigitational fashion, held another in his hands.

Harlan thought: To the point, now.

He began, a trifle too loudly, a bit too truculently, "There is a girl in the 482nd--"

Twissell frowned, waved one hand quickly as though brushing an unpleasant matter hastily to one side. "I know, I know. She will not be disturbed, nor you. All will be well. I will see to it."

"Do you mean--"

"I tell you I know the story. If the matter has troubled you, it need trouble you no more."

Harlan stared at the old man, stupefied. Was this all? Though he had thought intently of the immensity of his power, he had not expected so clear a demonstration.

But Twissell was talking again.

"Let me tell you a story," he began, with almost the tone he would have used in addressing a newly inducted Cub. "I had not thought this would be necessary, and perhaps it still isn't, but your own researches and insight deserve it."

He stared at Harlan quizzically and said, "You know, I still can't quite believe that you worked this out on your own," then went on:

"The man most of Eternity knows as Vikkor Mallansohn left the record of his life behind him after he died. It was not quite a diary, not quite a biography. It was more of a guide, bequeathed to the Eternals he knew would someday exist. It was enclosed in a volume of Time-stasis which could be opened only by the Computers of Eternity, and which therefore remained untouched for three Centuries after his death, until Eternity was established and Senior Computer Henry Wadsman, the first of the great Eternals, opened it. The document has been passed along in strictest security since, along a line of Senior Computers ending with myself. It is referred to as the Mallansohn memoir.

"The memoir tells the story of a man named Brinsley Sheridan Cooper, born in the 78th, inducted as a Cub into Eternity at the age of twenty-three, having been married for a little over a year, but having been, as yet, childless.

"Having entered Eternity, Cooper was trained in mathematics by a Computer named Laban Twissell and in Primitive sociology by a Technician named Andrew Harlan. After a thorough grounding in both disciplines, and in such matters as temporal engineering as well, he was sent back to the 24th to teach certain necessary techniques to a Primitive scientist named Vikkor Mallansohn.

"Once having reached the 24th, he embarked first on a slow process of adjusting himself to the society. In this he benefited a great deal from the training of Technician Harlan and the detailed advice of Computer Twissell, who seemed to have an uncanny insight into some of the problems he was to face.

"After the passage of two years, Cooper located one Vikkor Mallansohn, an eccentric recluse in the California backwoods, relationless and friendless but gifted with a daring and unconventional mind. Cooper made friends slowly, acclimated the man to the thought of having met a traveler from the future still more slowly, and set about teaching the man the mathematics he must know.

"With the passage of time, Cooper adopted the other's habits, learned to shift for himself with the help of a clumsy Diesel-oil electric generator and with wired electrical appliances which freed them of dependence on power beams.

"But progress was slow and Cooper found himself something less than a marvelous teacher. Mallansohn grew morose and unco-operative and then one day died, quite suddenly, in a fall down a canyon of the wild, mountainous country in which they lived. Cooper, after weeks of despair, with the ruin of his lifework and, presumably, of all Eternity, staring him in the eye, decided on a desperate expedient. He did not report Mallansohn's death. Instead, he slowly took to building, out of the materials at hand, a Temporal Field.

"The details do not matter. He succeeded after mountains of drudgery and improvisation and took the generator to the California Institute of Technology, just as years before he had expected the real Mallansohn to do.

"You know the story from your own studies. You know of the disbelief and rebuffs he first met, his period under observation, his escape and the near-loss of his generator, the help he received from the man at the lunch counter whose name he never learned, but who is now one of Eternity's heroes, and of the final demonstration for Professor Zimbalist, in which a white mouse moved backward and forward in time. I won't bore you with any of that.

"Cooper used the name of Vikkor Mallansohn in all this because it gave him a background and made him an authentic product of the 24th. The body of the real Mallansohn was never recovered.

"In the remainder of his life, he cherished his generator and cooperated with the Institute scientists in duplicating it. He dared do no more than that. He could not teach them the Lefebvre equations without outlining three Centuries of mathematical development that was to come. He could not, dared not hint at his true origin. He dared not do more than the real Vikkor Mallansohn had, to his knowledge, done.

"The men who worked with him were frustrated to find a man who could perform so brilliantly and yet was unable to explain the whys of his performance. And he himself was frustrated too, because he foresaw, without in any way being able to quicken, the work that would lead, step by step, to the classic experiments of Jan Verdeer, and how from that the great Antoine Lefebvre would construct the basic equations of Reality. And how, after that, Eternity would be constructed.

"It was only toward the end of his long life that Cooper, staring into a Pacific sunset (he describes the scene in some detail in his memoir) came to the great realization that he was Vikkor Mallansohn; he was not a substitute but the man himself. The name might not be his, but the man history called Mallansohn was really Brinsley Sheridan Cooper.

"Fired with that thought, and with all that implied, anxious that the process of establishing Eternity be somehow quickened, improved, and made more secure, he wrote his memoir and placed it in a cube of Time-stasis in the living room of his house.

"And so the circle was closed. Cooper-Mallansohn's intentions in writing the memoir were, of course, disregarded. Cooper must go through his life exactly as he had gone through it. Primitive Reality allows of no changes. At this moment in physiotime, the Cooper you know is unaware of what lies ahead of him. He believes he is only to instruct Mallansohn and to return. He will continue to believe so until the years teach him differently and he sits down to write his memoir.

"The intention of the circle in Time is to establish the knowledge of Time-travel and of the nature of Reality, to build Eternity, ahead of its natural Time. Left to itself, mankind would not have learned the truth about Time before their technological advances in other directions had made racial suicide inevitable."

Harlan listened intently, caught up in the vision of a mighty circle in Time, closed upon itself, and traversing Eternity in part of its course. He came as close to forgetting Noys, for the moment, as he ever could.

He asked, "Then you knew all along everything you were to do, everything I was to do, everything I have done."

Twissell, who seemed lost in his own telling of the tale, his eyes peering through a haze of bluish tobacco smoke, came slowly to life. His old, wise eyes fixed themselves on Harlan and he said reproachfully, "No, of course not. There was a lapse of decades of physiotime between Cooper's stay in Eternity and the moment when he wrote his memoir. He could remember only so much, and only what he himself had witnessed. You should realize that."

Twissell sighed and he drew a gnarled finger through a line of updrafting smoke, breaking it into little turbulent swirls. "It worked itself out. First, I was found and brought to Eternity. When, in the fullness of physiotime, I became a Senior Computer, I was given the memoir and placed in charge. I had been described as in charge, so I was placed in charge. Again in the fullness of physiotime, you appeared in the changing of a Reality (we had watched your earlier analogues carefully), and then Cooper.

"I filled in the details by using my common sense and the services of the Computaplex. How carefully, for instance, we instructed Educator Yarrow in his part while betraying none of the significant truth. How carefully, in his turn, he stimulated your interest in the Primitive.

"How carefully we had had to keep Cooper from learning anything he did not prove he had learned by reference in the memoir." Twissell smiled sadly. "Sennor amuses himself with matters such as this. He calls it the reversal of cause and effect. Knowing the effect, one adjusts the cause. Fortunately, I am not the cobweb spinner Sennor is.

"I was pleased, boy, to find you so excellent an Observer and Technician. The memoir had not mentioned that since Cooper had no opportunity to observe your work or evaluate it. This suited me. I could use you in a more ordinary task that would make your essential one less noticeable. Even your recent stay with Computer Finge fitted in. Cooper mentioned a period of your absence during which his mathematical studies were so sharpened that he longed for your return. Once, though, you frightened me."

Harlan said, at once, "You mean the time I took Cooper along the kettle ways."

"How do you come to guess that?" demanded Twissell.

"It was the one time you were really angry with me. I suppose now it went against something in the Mallansohn memoir."

"Not quite. It was just that the memoir did not speak of the kettles. It seemed to me that to avoid mention of such an outstanding aspect of Eternity meant he had little experience with it. It was my intention therefore to keep him away from the kettles as much as possible. The fact that you had taken him upwhen in one disturbed me greatly, but nothing happened afterward. Things continued as they should, so all is well."

The old Computer rubbed one hand slowly over the other, staring at the young Technician with a look compounded of surprise and curiosity. "And all along you've been guessing this. It simply astonishes me. I would have sworn that even a fully trained Computer could not have made the proper deductions, given only the information you had. For a Technician to do it is uncanny." He leaned forward, tapped Harlan's knee lightly. "The Mallansohn memoir says nothing about your life after Cooper's leaving, of course."

"I understand, sir," said Harlan.

"We will be free then, in a manner of speaking, to do as we please with it. You show a surprising talent that must not be wasted. I think you are meant for something more than a Technician. I promise nothing now, but I presume that you realize that Computership is a clistinct possibility."

It was easy for Harlan to keep his dark face expressionless. He had had years of practice for that.

He thought: An additional bribe.

But nothing must be left to conjecture. His guesses, wild and unsupported at the start, arrived at by a freak of insight in the course of a very unusual and stimulating night, had become reasonable as the result of directed library research. They had become certainties now that Twissell had told him the story. Yet in one way at least there had been a deviation. Cooper was Mallansohn.

That had simply improved his position, but, wrong in one respect, he might be wrong in another. He must leave nothing to chance, then. Have it out! Make certain!

He said levelly, almost casually, "The responsibility is great for me, also, now that I know the truth."

"Yes, indeed?"

"How fragile is the situation? Suppose something unexpected were to happen and I were to miss a day when I ought to have been teaching Cooper something vital."

"I don't understand you."

(Was it Harlan's imagination, or had a spark of alarm sprung to life in those old, tired eyes?)

"I mean, can the circle break? Let me put it this way. If an unexpected blow on the head puts me out of action at a time when the memoir distinctly states I am well and active, is the whole scheme disrupted? Or suppose, for some reason, I deliberately choose not to follow the memoir. What then?"

"But what puts all this in your mind?"

"It seems a logical thought. It seems to me that by a careless or willful action, I could break the circle, and well, what? Destroy Eternity? It seems so. If it is so," Harlan added composedly, "I ought to be told so that I may be careful to do nothing unfitting. Though I imagine it would take a rather unusual circumstance to drive me to such a thing."

Twissell laughed, but the laughter rang false and empty in Harlan's ear. "This is all purely academic, my boy. Nothing of this will happen since it hasn't happened. The full circle will not break."

"It might," said Harlan. "The girl of the 482nd--"

"Is safe," said Twissell. He rose impatiently. "There's no end to this kind of talk and I have quite enough of logic-chopping from the rest of the subcommittee in charge of the project. Meanwhile, I have yet to tell you what I originally called you here to hear and physiotime is still passing. Will you come with me?

Harlan was satisfied. The situation was clear and his power unmistakable. Twissell knew that Harlan could say, at will: "I will no longer have anything to do with Cooper." Twissell knew Harlan could at any moment destroy Eternity by giving Cooper significant information concerning the memoir.

Harlan had known enough to do this yesterday. Twissell had thought to overwhelm him with the knowledge of the importance of his task, but if the Computer had thought to force Harlan into line in that way, he was mistaken.

Harlan had made his threat very clear with respect to Noys's safety, and Twissell's expression as he had barked, "Is safe," showed he realized the nature of the threat.

Harlan rose and followed Twissell.

Harlan had never been in the room they now entered. It was large and looked as though walls had been knocked down for its sake. It had been entered through a narrow corridor which had been blocked off by a force-screen that did not go down until after a pause sufficient for Twissell's face to be scanned thoroughly by automatic machinery.

The largest part of the room was filled by a sphere that reached nearly to the ceiling. A door was open, showing four small steps leading to a well-lit platform within.

Voices sounded from inside and even as Harlan watched, legs appeared in the opening and descended the steps. A man emerged and another pair of legs appeared behind him. It was Sennor of the Allwhen Council and behind him was another of the group at the breakfast table.

Twissell did not look pleased at this. His voice, however, was restrained. "Is the subcommittee still here?"

"Only we two," said Sennor casually, "Rice and myself. A beautiful instrument we have here. It has the level of complexity of a spaceship."

Rice was a paunchy man with the perplexed look of one who is accustomed to being right yet finds himself unaccountably on the losing side of an argument. He rubbed his bulbous nose and said, "Sennor's mind is running on space-travel lately."

Sennor's bald head glistened in the light. "It's a neat point, Twissell," he said. "I put it to you. Is space-travel a positive factor or a negative factor in the calculus of Reality?"

"The question is meaningless," said Twissell impatiently. "What type of space-travel in what society under what circumstances?"

"Oh, come. Surely there's something to be said concerning spacetravel in the abstract."

"Only that it is self-limiting, that it exhausts itself and dies out."

"Then it is useless," said Sennor with satisfaction, "and therefore it is a negative factor. My view entirely."

"If you please," said Twissell, "Cooper will be here soon. We will need the floor clear."

"By all means." Sennor hooked an arm under that of Rice and led him away. His voice declaimed clearly as they departed. "Periodically, my dear Rice, all the mental effort of mankind is concentrated on space-travel, which is doomed to a frustrated end by the nature of things. I would set up the matrices except that I am certain this is obvious to you. With minds concentrated on space, there is neglect of the proper development of things earthly. I am preparing a thesis now for submission to the Council recommending that Realities be changed to eliminate all space-travel eras as a matter of course."

Rice's treble sounded. "But you can't be that drastic. Space-travel is a valuable safety-valve in some civilizations. Take Reality 54 of the 290th, which I happen to recall offhand. Now there--"

The voices cut off and Twissell said, "A strange man, Sennor. Intellectually, he's worth two of any of the rest of us, but his worth is lost in leapfrog enthusiasms."

Harlan said, "Do you suppose he can be right? About space-travel, I mean."

"I doubt it. We'd have a better chance of judging if Sennor would actually submit the thesis he mentioned. But he won't. He'll have a new enthusiasm before he's finished and drop the old. But never mind--" He brought the flat of his hand against the sphere so that it rang resoundingly, then brought his hand back so that he could remove a cigarette from his lip. He said, "Can you guess what this is, Technician?"

"Harlan said, "It looks like an outsize kettle with a top."

"Exactly. You're right. You've got it. Come on inside."

Harlan followed Twissell into the sphere. It was large enough to hold four or five men, but the interior was absolutely featureless. The floor was smooth, the curved wall was broken by two windows. That was all.

"No controls?" asked Harlan.

"Remote controls," said Twissell. He ran his hand over the smoothness of the wall and said, "Double walls. The entire interwall volume is given over to a self-contained Temporal Field. This instrument is a kettle that is not restricted to the kettle shafts but can pass beyond the downwhen terminus of Eternity. Its design and construction were made possible by valuable hints in the Mallansohn memoir. Come with me."

The control room was a cut-off corner of the large room. Harlan stepped in and stared somberly at immense bus bars.

Twissell said, "Can you hear me, boy?"

Harlan started and looked about. He had not been aware that Twissell had not followed him inside. He stepped automatically to the window and Twissell waved to him. Harlan said, "I can hear you, sir. Do you want me outside?"

"Not at all. You are locked in."

Harlan sprang to the door and his stomach turned into a series of cold, wet knots. Twissell was correct and what in Time was going on?

Twissell said, "You will be relieved to know, boy, that your responsibility is over. You were worried about that responsibility; you asked searching questions about it; and I think I know what you meant. This should not be your responsibility. It is mine alone. Unfortunately, we must have you in the control room, since it is stated that you were there and handled the controls. It is stated in the Mallansohn memoir. Cooper will see you through the window and that will take care of that.

"Furthermore, I will ask you to make the final contact according to instructions I will give you. If you feel that that, too, is too great a responsibility, you may relax. Another contact in parallel with yours is in charge of another man. If, for any reason, you are unable to operate the contact, he will do so. Furthermore, I will cut off radio transmission from within the control room. You will be able to hear us but not to speak to us. You need not fear, therefore, that some involuntary exclamation from you will break the circle."

Harlan stared helplessly out the window.

Twissell went on, "Cooper will be here in moments and his trip to the Primitive will take place within two physiohours. After that, boy, the project will be over and you and I will be free."

Harlan was plunging chokingly through the vortex of a waking nightmare. Had Twissell tricked him? Had everything he had done been designed only to get Harlan quietly into a locked control room? Having learned that Harlan knew his own importance, had he improvised with diabolical cleverness, keeping him engaged in conversation, drugging his emotions with words, leading him here, leading him there, until the time was ripe for locking him in?

That quick and easy surrender over Noys. She won't be hurt, Twissell had said. All will be well.

How could he have believed that! If they were not going to harm her, or touch her, why the temporal barrier across the kettleways at the 100,000th? That alone should have given Twissell completely away.

But because he (fool!) wanted to believe, he allowed himself to be led through those last physiohours blindly, placed inside a locked room where he was no longer needed, even to close the final contact.

In one stroke he had been robbed of his essentiality. The trumps in his hand had been neatly maneuvered into deuces and Noys was out of his reach forever. What punishment might lie in wait for him did not concern him. Noys was out of his reach forever.

It had never occurred to him that the project would be so close to its end. That, of course, was what had really made his defeat possible.

Twissell's voice sounded dimly. "You'll be cut off now, boy."

Harlan was alone, helpless, useless...