Against the Fall of Night by Arthur C. Clarke

if I don’t come back at once anything may happen.”
    Seranis smiled slightly.
    “We have given that a good deal of thought,” she admitted. “There are men working on the problem now—we will see if they have been successful.”
    Alvin was annoyed at having overlooked something so obvious. He knew that the engineers of the past had built for eternity—his journey to Lys had been proof of that. Yet it gave him a shock when the chromatic mist on the visiphone screen drifted aside to show the familiar outlines of Rorden’s room.
    The Keeper of the Records looked up from his desk. His eyes lit when he saw Alvin.
    “I never expected you to be early,” he said—though there was relief behind the jesting words. “Shall I come to meet you?”
    While Alvin hesitated, Seranis stepped forward and Rorden saw her for the first time. His eyes widened and he leaned forward as if to obtain a better view. The movement was as useless as it was automatic: Man had not lost it even though he had used the visiphone for a thousand million years.
    Seranis laid her hands on Alvin’s shoulders and began to speak. When she had finished Rorden was silent for a while.
    “I’ll do my best,” he said at length. “As I understand it, the choice lies between sending Alvin back to us under some form of hypnosis—or returning him with no restrictions at all. But I think I can promise that even if it learns of your existence, Diaspar will continue to ignore you.”
    “We don’t overlook that possibility,” Seranis replied with just a trace of pique. Rorden detected it instantly.
    “And what of myself?” he asked with a smile. “I know as much as Alvin now.”
    “Alvin is a boy,” replied Seranis quickly, “but you hold an office as ancient as Diaspar. This is not the first time Lys has spoken to the Keeper of the Records, and he has never betrayed our secret yet.”
    Rorden made no comment: he merely said: “How long do you wish to keep Alvin?”
    “At the most, five days. The Council meets three days from now.”
    “Very well: for the next five days, then, Alvin is extremely busy on some historical research with me. This won’t be the first time it’s happened—but we’ll have to be out if Jeserac calls.”
    Alvin laughed.
    “Poor Jeserac! I seem to spend half my life hiding things from him.”
    “You’ve been much less successful than you think,” replied Rorden, somewhat disconcertingly. “However, I don’t expect any trouble. But don’t be longer than the five days!”
    When the picture had faded, Rorden sat for a while staring at the darkened screen. He had always suspected that the world communication network might still be in existence, but the keys to its operation had been lost and the billions of circuits could never be traced by man. It was strange to reflect that even now visiphones might be called vainly in the lost cities. Perhaps the time would come when his own receiver would do the same, and there would be no Keeper of the Records to answer the unknown caller….
    He began to feel afraid. The immensity of what had happened was slowly dawning upon him. Until now, Rorden had given little thought to the consequences of his actions. His own historical interests, and his affection for Alvin, had been sufficient motive for what he had done. Though he had humored and encouraged Alvin, he had never believed that anything like this could possibly happen.
    Despite the centuries between them, the boy’s will had always been more powerful than his own. It was too late to do anything about it now: Rorden felt that events were sweeping him along towards a climax utterly beyond his control.
    “ IS ALL THIS REALLY NECESSARY ,” SAID ALVIN , “ IF WE ARE only going to be away for two or three days? After all, we have a synthesizer with us.”
    “Probably not,” answered Theon, throwing the last food-containers into the little ground-car. “It may seem an odd custom, but we’ve never synthesized some of our finest