The Depths of Time

by Roger MacBride Allen

  The ship heeled over hard to her new heading, and Koffield watched the symbol-logic displays of the debris rushing toward them, and of their own weapons fire heading out. He looked to the two countdowns. The seconds remaining until debris cloud impact, and railgun time-on-target, clicked down almost in lockstep with each other.

  Ten seconds. Nine. Eight. Seven. Six. Five. Four. Three. Two. One.

  “Multiple hits on target—” the detection officer began, but with a crash and a thud, the lights died on the bridge.

  Pitch-blackness blanketed the bridge. Voices—shouts, cries, calm, professional reporting—filled the darkness.

  Nothing. There was nothing at all he could do. Not until there was light, and power. Nothing until—

  The nexus control panel lit back up, a message already on it. nexus control system receives and accepts confirmation of instruction to deactivate portal nexus “d” permanently. nexus control system advises that this will be the last chance to countermand the instruction, send second confirmation within sixty seconds, any other action or lack of action will result in cancellation of instruction.

  The screen flickered once and then died again.

  How long had that message been there before he could see it? How long had the display been blank, unable to show him the words? Five seconds? Twenty? Koffield fumbled for the control system keyboard in the all-but-complete darkness. Working blind, he laboriously keyed in the second confirmation. He could not see the words he was keying in. At last he had the command keyed in as best he could, but then he held back. He had no way of knowing if he had indeed keyed the command in properly. What if he had typed it in wrong, and the Artlnt refused to accept the scrambled message? How long did he have before the sixty-second countdown was over and the Artlnt canceled the deactivation sequence? Had the keyboard even taken his keystrokes, or had the power failure cut the keyboard as well? If the main lights would only come on, he could check the command and resend it. But if he waited too long for the lights, the system would cancel the sequence anyway.

  How long to wait? Koffield decided to give it twenty seconds, and counted it out to himself, doing his best to guess how long a second was. He hit the send key.

  A few seconds, or a few years, later, somewhere deep in the bowels of the ship, a power relay reset, and the bridge bloomed back into existence as the emergency lights came on, turning utter darkness to a compartment half-lit, half-shrouded in gloom. Koffield blinked as his eyes adjusted, and then saw what he had sent on the screen.

  ANTON KOFFIELD COMMANDING UPHOLDER SENDS SECOND CONFROMATIUON OF INSTRUCTION TO NEXUS CONTRL SYSTEM TO DEACTIVATE PORTAL NEXUS “d” PERMANENTLY.

  The indicators showed the system had received the instruction, but they had just gone through a major power crisis. Koffield could imagine a half dozen kinds of power failures, trips, and flares that could have caused the message-send to get scrambled or lost, or caused the system to show a false positive. The Artlnt system ought to be able to parse through and interpret the command in spite of the miskeyed words, but there was no way to know for sure. Typing in the command again would either reassure the Artlnt—or make it suspicious of a trick and cause it to abort.

  There was, in short, nothing he could do that would not just as likely make things worse instead of better.

  Leave it. Leave it alone. Nothing he could do.

  There was no telling precisely how long the Artlnt would take to work its way through the complexities of the situation, but Koffield had no doubt this step, this last, irrevocable step, would take longer than any other. Every other decision the Artlnt had made included the possibility of stopping, of backing off from a full shutdown. So long as one nexus remained, the system could be rebuilt. But with the last nexus gone, there was no way back. The Artlnt would think longer and harder before launching over that precipice.

  “Damage status?” he asked.

  “Five small debris strikes to bow of the ship,” the ship systems officer reported. “Laser cannon off-line but possibly repairable. Railgun system badly damaged. Detection system highly questionable but marginally functional for the moment. Main power system appears to be fully functional but is still recovering from power surges. No other damage reported.”

  “Very well,” Koffield said. His displays finished rebuilding themselves as he watched. Even with the detectors damaged, he could see that Intruder Three had definitely taken at least one hit. The detectors were only rendering a flickering dot of light, but that was enough to tell Koffield a great deal. The dot was swelling and fading, while at the same time pulsing in overall brightness—the classic fingerprint of a ship tumbling and venting violently. Intruder Three was still headed straight for the wormhole, but unless it restored full attitude control in very short order, it would surely be torn apart by tidal stresses as it closed in on the singularity. It was as good as out of the game.

  Even as he watched, new disaster overtook Three. It brightened abruptly, then flared over into blackness. Koffield needed only a moment to figure out what had happened. The debris cloud from the interceptor collision had just swept past Three, and punished it far more severely than it had the Upholder.

  Now indeed was the chessboard swept clean. Ship Five was departing as rapidly as she could, under full emergency thrust, her engines no doubt scrambling all of her rear detectors and communications. She could not see what was going on astern of her course, and could not send or receive messages. She might, if she survived, serve as a witness to what had already happened, but otherwise her part in the disaster was over.

  That left only two ships still in the game—Intruder Five and the Upholder. Everything and everyone else had been destroyed—smashed into rubble, or swallowed up by the singularity.

  In a sense, even the Upholder was now out of the game. She had shot her bolt. Her weapons were spent or wrecked, her detection systems half-blind. There was nothing left that she could do to stop the last Intruder. Koffield didn’t even have the engine power to come about in time and put his ship on a suicide intercept. Nothing left to do but survive.

  All that mattered now was that the Upholder hold together until the nexus portal control Artlnt processed the last confirmation and acted on it, killing Nexus D, and closed the last door into the timeshaft before Intruder Five went through it, in twenty minutes and five seconds. Koffield could do nothing, dared do nothing,, until the Artlnt had done its job.

  Twenty minutes. Nineteen, now. Too short a time, and too long. Not enough time to act, but more than enough time to think, to reflect on what was to come. Either bitter failure, and Intruder Five proceeding through the worm-hole despite all the lives and treasure he had spent—or else equally bitter victory.

  Even if he succeeded in stopping the last Intruder, then what was there for him, for any of his crew? They could never go home into the past again. They might, after a long and arduous journey, reach a safe port somewhere here on the uptime side of the timeshaft wormhole. But then what? What lives could there be for any of them? What life especially for Koffield, the man who had ordered the destruction of the post he was meant to protect?

  But first they had to stay alive, and keep the ship functioning long enough to stop the Intruder. Koffield brought up the ship-systems repeater and studied it closely for a moment. The ship’s repair crews were working fast, putting the ship back together as best they could. They needed no guidance, no instruction, from him. Nor did any other member of the crew. He had made his bidding known, and they were doing it. His work was done. Nothing left but to watch its sequel unfold.

  Fifteen minutes, five seconds left.

  Here and there, slowly, fitfully, small parts of the bridge and the ship came back to life around him. Main power came back on-line. The ventilation came back to life with a quiet whir, though he had not even been consciously aware it had failed. Koffield had seen the repeater display report that the ventilators were off-line, but somehow he had not equated that with the too-still, too-stale air of the bridge.<
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  Still fifteen minutes, five seconds. Time. Time was what he was here to defend, what he was sacrificing everything for. How was it that time had stopped? No. There. Time had started up again, never really stopped. Fifteen minutes, four seconds. Three seconds. Two seconds.

  He stared at the clock, half of him willing time to move forward, while the other half wished most devoutly for time to stand still until the nexus control system Artlnt had processed the last command, compared it to the situation, and judged whether or not it should be acted upon.

  Strange indeed that they had all almost ceased wondering who, or what, the Intruders were, or what they wanted, or where and what they came from. So far as the attitude of Koffield and the crew went, they simply were, like a force of nature. None of them had seen the Intruders as anything more than dots of light or symbol-logic indicators. They had no idea what the Intruder ships looked like. It took a real effort of concentration to remember the Intruders were directed by intelligence, rather than by some malevolent natural force. They were machines.

  And now it came down to Koffield’s machine versus the Intruders’ machines. It was even something of a relief that it would come down to what the machine chose. If the Artlnt decided, at the last, that it could not, should not, close the final nexus, then Koffield would be delighted to be wrong. He knew he would likely face court-martial, prison, perhaps execution—but even that would be preferable to the doom and disaster it would unleash if the timeshaft was indeed slammed shut. And if the Artlnt did indeed destroy the final nexus, then, perhaps, he could convince himself that it was the Artlnt, and not Anton Koffield, that had done the final deed. A tempting and comforting notion, that.

  But no. This was his doing, his responsibility. He hadn’t sworn an oath, taken an officer’s commission, and accepted command of the Upholder just to hide behind an Artificial Intelligence. Right or wrong, win or lose, this battle belonged to him.

  “Sir, we’re picking up the fringe of some sort of radio transmission from Intruder Five,” the comm officer reported. “High probability it’s signaling Nexus D.”

  No surprise there, but it was not exactly encouraging news. What if the controller system aboard Nexus D decided to accept commands from the Intruder, and ignore those from the Artlnt aboard Upholder?

  Koffield flipped his prime repeater display over to comm and shook his head in frustration. They were only just barely able to detect the presence of a signal at all. Probably the Intruder was sending on a tight beam. If they had still had the use of the detection equipment that had been destroyed in the first attack of the Intruders, and a modicum of time, the comm department probably would have been able to reconstruct the message in full. But half the ship’s detection gear was shot away, damage-control parties were still at work, and there were only thirteen minutes, eight seconds left until the end of things, one way or the other.

  The end of things . ..

  For the first time, Koffield allowed himself the luxury— and the horror—of considering what might happen, what might change, if the Intruder got through to the past. All the history between the downtime and uptime ends of the Circum Central Wormhole was at risk. Every person born, every idea created, every human action of the last seventy-nine years could be turned upside down and inside out. And what was there to prevent this Intruder from replicating itself, or to prevent its creator from creating more? What to stop it from seeking out the uptime ends of other worm-holes, back there, seventy-nine years in the past? And if the Intruder could punch through this timeshaft worm-hole, what was to prevent its forcing its way through others? If it had the timeshaft-wormhole control codes, what was there to keep the Intruder from going back, and back, and back, to the very beginning of the timeshaft-wormhole transportation system?

  Thousands of years of history, of triumph and failure, lay open and exposed to every danger. What was to stop the Intruder from dropping back far enough in time to prevent the building of the Upholder, or the founding of the Chronologic Patrol itself? The ripples of time paradox could send chaos sweeping down the years.

  And there was nothing he could do. All his power spent, his last throw of the die already made, all Captain Anton Koffield could do was watch the minutes and the seconds die.

  He stared at the displays, his gaze shifting endlessly from comm to detection to weapons to navigation, and then back to the only one that still mattered, back to the nexus control Artint. The bridge went quiet, almost silent, as the end drew near. Ten minutes. Nine minutes. Eight minutes. And still the Artint did not respond, did not act.

  Again and again, Koffield fought back the temptation to relink to the Artint and reissue his instructions, or at least query on status. Everything he knew about Artlnts told him that any distraction, any interference, would likely be disastrous. The Artint had the data it needed, the data it expected. In a situation this complex, this unexpected, and this dangerous, giving it extraneous information could only add to the number of variables it had to juggle.

  A flicker on the comm repeater display. The Intruder was transmitting again. “Comm,” Koffield said, “can you make anything more of that?”

  “Doing a pattern match. Stand by. Sir, maybe a little bit of good news. As best I can tell, that was a repeat of their last signal—and I haven’t seen any sort of response from the nexus itself. It sends a mirror reply of any command it receives and accepts. The Intruder is having some trouble.”

  “Very good,” Koffield said. “That’s a very good sign indeed.” It might well mean that the nexus Artint had put a block on Nexus D’s communications system, ordering it to ignore commands from any other source. And that in turn would mean that the Artint had analyzed the situation properly, and would blow Nexus D in time.

  It sounded hopeful, though it was a hell of a lot to read into a silence—but silence was all they had.

  Seven minutes. Six minutes. The wait went on forever. Koffield’s universe shrank down to nothing but his displays, and the numbers and logic symbols on them. The bridge, the ship, the exterior reality represented by the displays, all faded away. There was nothing but the shifting countdown numbers, the dot representing the Intruder creeping toward Nexus D, the blank status line on the nexus control Artlnt display.

  It was a standoff, but a standoff that favored the Upholder. Intruder Five had long since gone past the point of no return. It was headed straight for the singularity, falling like a rock, and nothing could stop it now. It could no longer escape the singularity’s gravity well. It was going in, no matter what.

  Koffield had ordered the Artlnt to destroy Nexus D, wreck it, slam the door shut and seal it for all time. The Artlnt had not yet decided whether to send that order. Intruder Five was ordering Nexus D to open itself, and let the Intruder through. If the Artlnt sent the destruct command and Nexus D accepted it and refused the orders from the Intruder, the Intruder would crash into the singularity. If the nexus refused both sets of orders, it would remain shut, and the Intruder would still slam into the singularity to be utterly destroyed.

  The Intruder could only win, could only cause the nexus to open and allow it through the wormhole, if the nexus accepted the Intruder’s orders and refused those from the Upholder’s Artlnt. The logic sounded hopeful— but the Intruder had been doing all the winning so far.

  Five minutes. Four.

  Was there anything left undone? Anything left to do at all? Koffield could hear a stifled sob, and the sound of someone quietly weeping, somewhere on the half-darkened bridge. All his life, all his career, there had always been some action to take, some choice left. Nothing.

  “Intruder sending commands again,” the comm officer reported, even as Koffield watched the same information pop up on his repeater.

  “Is it repeating the same sequence?” Koffield asked.

  “As best I can tell, sir. Our aspect angle is shifting relative to the Intruder, and we’re getting less of the transmission every time.’’

  “Very well.” Let the Intruder ke
ep trying. In three minutes’ time it would be too late. Nexus D would stay closed, the Intruder would impact on the singularity, and it would be all over.

  Two minutes.

  “Sir! Detecting response from Nexus D. Odds ninety-five plus it’s a mirror reply to the Intruder.”

  The news was a sharp, hard blow to the gut. Where the hell was the Artlnt? Had it been blown away, wrecked or damaged by the last strike to the ship? Ninety seconds to go. Not even rime left to restart the sequence of command and confirmation. The Artlnt should have responded, yes or no, Koffield decided. There was some malfunction. He would leave it as long as he could, and then try the restart, hope that the urgency of the situation would get the Artlnt to act faster. At the sixty-second mark he would try it again. His hands were poised over the keypad. nexus control system reports unauthorized access attempt. stand by.

  Koffield stared at the display, the sweat standing out on his forehead. Stand by? How long could he—He checked the countdown clock. Seventy seconds until Intruder Five hit the singularity. And who did nexus control think was unauthorized? Koffield or the Intruder? nexus control system reports loss of control over nexus. attempting to regain control and deactivate portal nexus “d” permanently.

  “Nexus D opening!” the detection officer shouted. “Oh, my God, it’s opening. Nexus D open, stable, active, and operational.”

  Koffield pulled his hands back from the keypad, his eyes wide with horror. It was the disaster, the catastrophe, that all of the Chronologic Patrol had been built to prevent. And it had come to pass, here, on his watch.

  Sixty seconds. The past would be attacked—by what or whom? for what reason?—in sixty seconds. The Intruder would get past the downtime relief ship. Of that he had no doubt. It would get past, accelerate to those same impossible speeds, and roam at will through the past, carrying detailed information—about what, for what, who could know?— from the future.