Poul Anderson - The Shield of Time

“Anyhow, naturally, our bases in the twelfth century started communicating with those downtime. This led to contact with Unattached Agent Komozino.” Everard gestured at her. “She happened to be in Egypt—uh, Eighteenth Dynasty, did you say?—tracking down an expedition from her home millennium that’d gone back in search of cultural inspiration and evidently gotten lost…. No, plain to see whatever became of it, there was no noticeable effect on history…. She took charge of the entire emergency operation, pending the availability of more people with the same rank. A data scan suggested me, so she came in person to inform and confer.” Everard braced himself. “At the moment, unless a Danellian shows up, we, ladies and gentlemen, are on the edge of the effort to salvage the future.”

“Us?” cried a young man. Everard knew him peripherally, French, period of Louis XIV and assigned to that same milieu, as most agents were assigned to their own eras. It meant he was bright. The Patrol got few recruits from before the First Industrial Revolution, and very few from prescientific societies. A person who hadn’t been raised in that style of thinking was seldom able to assimilate the concepts. At that, this lad was having difficulties. “But, sir, there must be hundreds, thousands of our kind active before the crisis date. Shall we not gather them all together?”

Everard shook his head. “No. We’re in deep enough trouble already. The vortices we could generate—”

“Perhaps I can make it a little clearer,” Komozino offered crisply. “Yes, quite probably most Patrol personnel go into the pre-medieval past, if only on vacation, like you. They are present, so to speak, there and then. Often more than once. For example, Agent Everard has been active in settings as diverse as early Phoenicia, Achaémenid Persia, post-Roman Britain, and viking Scandinavia. He has repeatedly come to this lodge for rest and recreation, at various points of its existence, both downtime and uptime of the present moment. Why should we not call on these Everards also? Certainly two Unattached make an insufficient cadre of leaders.

“The fact is, we have not done so. We will not do so. If we did, that would change reality again and again, hopelessly, beyond any possibility of comprehension, let alone control. No, if we survive what is ahead of us and prevail over this misfortune, we will not double back on our world lines and warn ourselves to beware. Never! If you try it, you will find that your conditioning against such antics is as powerful as your conditioning against revealing to any unauthorized person that time travel occurs.

“The mission of the Patrol is precisely to maintain the ordered progression of history, of cause and effect, human will and human action. Often this is tragic, and the temptation to intervene is almost overwhelming. It must be resisted. That way lies chaos.

“And if we are to execute our duty, we must constrain ourselves to operate in as linearly causational a fashion as possible. We must always remember that every paradox is more than mortally dangerous.

“Therefore I have been flitting about, seeing to it that the news does not reach most of our remaining personnel. It is best confined to a few indispensables, and to selected off-duty individuals like yourselves. To further disturb the normal pattern of events is to risk obliteration and oblivion.”

Her stiff height sagged a little. “It has been hard,” she whispered. Everard wondered how much of her lifespan she had spent on that frantic task. It wasn’t just a matter of dashing from post to post, passing on the word here and hushing it up there. She had to know what she was doing. Mostly she must have been immersed in records, databases, evaluations of people and periods. The decisions must frequently be agonizing. Had she been at it weeks, months, years? Awed, he knew that such an intellectual achievement was altogether beyond him.

He had his own strengths, though. He took the word: “Remember too, friends, the Patrol does more than guard the integrity of time. That’s a job for special officers, and crucial though it is, it doesn’t occupy the main part of our activity. Most of us are police, with the traditional tasks of police.” We give advice, we regulate traffic, we arrest evildoers, we help travelers in distress, now and then we provide a shoulder to cry on. “Our fellow agents are busy. If we took them off their jobs, all hell would break loose.” Actually. Temporal lacked an exact equivalent of the homely English phrase in his mind. “So we’ll leave them alone, okay?”

“How shall we do that?” asked a twenty-first-century Nubian.

“We need a headquarters,” Everard said. “This’ll be it. We can seal it off for a certain limited slice of time without affecting anything else too much. That’d be impossible at the Academy, for instance. We’ll bring in people and equipment, and operate mainly out of this base. Just what we do—well, first we have to learn exactly what the situation is, then figure out our strategy. Sit tight for a few days.”

A smile, if it was a smile, twisted Komozino’s lips. “It is either grotesque or it is appropriate that Agent Everard is involved and that he shall commence out of here,” she remarked.

“May one request enlightenment as to the significance of the memsahib’s statement?” inquired a babu from the British Raj.

Komozino glanced at Everard. He scowled, shrugged, and said heavily, “It might possibly help, now, if you know. I was caught up in something like this earlier along my world line. A friend and I were staying here. Several years later than today, on the resort’s calendar. You’re aware how complicated the bookings get for as popular a spot as this. No matter. We decided to finish our furlough in my home, twentieth-century New York, and hopped there. It was totally foreign. Eventually we found out that Carthage had beaten Rome in the Punic Wars.” A gasp went around the room. Some persons half rose to their feet, sank down again and shivered. “What happened?” he heard, over and over.

Everard skipped dangers and deeds. The whole thing still hurt too much. “We went back well pastward, organized a force, and mounted an expedition to the critical point, a certain battle. We found a couple of outlaw time travelers, with energy weapons, on the Carthaginian side. Their idea was to make a godlike place for themselves in the ancient world. We nailed them before they could perform the action that counted, and … again history went the way it ought to, the way we remembered because we were born in it.” I condemned a world, uncounted billions of perfectly decent human beings, to nullity. They never were. None of what I had experienced ever happened. The scars on my spirit are simply there; nothing caused them.

“But I haven’t heard of this before, me!” protested the Frenchman.

“Certainly not,” Everard answered. “We don’t advertise stuff like that.”

“You saved my life, sir, my existence.”

“Thanks, but spare the gratitude. It isn’t called for. I did what I had to do.”

A Chinese, once a cosmonaut, narrowed his eyes and asked slowly, “Were you and your friend the only travelers who went uptime into that undesired universe?”

“By no means,” Everard replied. “Most skited straight back. Some didn’t; they never reported in anywhere; we can only guess they got trapped, maybe killed. My friend and I had a stiff time escaping. It happens that, out of those who returned, we were the ones able to take charge and organize the salvage operation—which happened to be a fairly simple one, or we could not have handled it, at least not without calling in more help. When it was complete, why, that post-Carthaginian world had never existed. People returning futureward from the past ‘always’ found the same world as ‘always.’”