because it was unmarked.

  But it was no closet. Swanson opened it warily, looked inside, thenmotioned Burckhardt to follow.

  It was a tunnel, metal-walled, brightly lit. Empty, it stretchedvacantly away in both directions from them.

  Burckhardt looked wondering around. One thing he knew and knew fullwell:

  No such tunnel belonged under Tylerton.

  * * * * *

  There was a room off the tunnel with chairs and a desk and what lookedlike television screens. Swanson slumped in a chair, panting.

  "We're all right for a while here," he wheezed. "They don't come heremuch any more. If they do, we'll hear them and we can hide."

  "Who?" demanded Burckhardt.

  The little man said, "Martians!" His voice cracked on the word and thelife seemed to go out of him. In morose tones, he went on: "Well, Ithink they're Martians. Although you could be right, you know; I'vehad plenty of time to think it over these last few weeks, after theygot you, and it's possible they're Russians after all. Still--"

  "Start from the beginning. Who got me when?"

  Swanson sighed. "So we have to go through the whole thing again. Allright. It was about two months ago that you banged on my door, late atnight. You were all beat up--scared silly. You begged me to helpyou--"

  "_I_ did?"

  "Naturally you don't remember any of this. Listen and you'llunderstand. You were talking a blue streak about being captured andthreatened, and your wife being dead and coming back to life, and allkinds of mixed-up nonsense. I thought you were crazy. But--well, I'vealways had a lot of respect for you. And you begged me to hide you andI have this darkroom, you know. It locks from the inside only. I putthe lock on myself. So we went in there--just to humor you--and alongabout midnight, which was only fifteen or twenty minutes after, wepassed out."

  "Passed out?"

  Swanson nodded. "Both of us. It was like being hit with a sandbag.Look, didn't that happen to you again last night?"

  "I guess it did," Burckhardt shook his head uncertainly.

  "Sure. And then all of a sudden we were awake again, and you said youwere going to show me something funny, and we went out and bought apaper. And the date on it was June 15th."

  "June 15th? But that's today! I mean--"

  "You got it, friend. It's _always_ today!"

  It took time to penetrate.

  Burckhardt said wonderingly, "You've hidden out in that darkroom forhow many weeks?"

  "How can I tell? Four or five, maybe. I lost count. And every day thesame--always the 15th of June, always my landlady, Mrs. Keefer, issweeping the front steps, always the same headline in the papers atthe corner. It gets monotonous, friend."

  IV

  It was Burckhardt's idea and Swanson despised it, but he went along.He was the type who always went along.

  "It's dangerous," he grumbled worriedly. "Suppose somebody comes by?They'll spot us and--"

  "What have we got to lose?"

  Swanson shrugged. "It's dangerous," he said again. But he went along.

  Burckhardt's idea was very simple. He was sure of only one thing--thetunnel went somewhere. Martians or Russians, fantastic plot or crazyhallucination, whatever was wrong with Tylerton had an explanation,and the place to look for it was at the end of the tunnel.

  They jogged along. It was more than a mile before they began to see anend. They were in luck--at least no one came through the tunnel tospot them. But Swanson had said that it was only at certain hours thatthe tunnel seemed to be in use.

  Always the fifteenth of June. Why? Burckhardt asked himself. Nevermind the how. _Why?_

  And falling asleep, completely involuntarily--everyone at the sametime, it seemed. And not remembering, never rememberinganything--Swanson had said how eagerly he saw Burckhardt again, themorning after Burckhardt had incautiously waited five minutes too manybefore retreating into the darkroom. When Swanson had come to,Burckhardt was gone. Swanson had seen him in the street thatafternoon, but Burckhardt had remembered nothing.

  And Swanson had lived his mouse's existence for weeks, hiding in thewoodwork at night, stealing out by day to search for Burckhardt inpitiful hope, scurrying around the fringe of life, trying to keep fromthe deadly eyes of _them_.

  Them. One of "them" was the girl named April Horn. It was by seeingher walk carelessly into a telephone booth and never come out thatSwanson had found the tunnel. Another was the man at the cigar standin Burckhardt's office building. There were more, at least a dozenthat Swanson knew of or suspected.

  They were easy enough to spot, once you knew where to look--for they,alone in Tylerton, changed their roles from day to day. Burckhardt wason that 8:51 bus, every morning of every day-that-was-June-15th, neverdifferent by a hair or a moment. But April Horn was sometimes gaudy inthe cellophane skirt, giving away candy or cigarettes; sometimesplainly dressed; sometimes not seen by Swanson at all.

  Russians? Martians? Whatever they were, what could they be hoping togain from this mad masquerade?

  Burckhardt didn't know the answer--but perhaps it lay beyond the doorat the end of the tunnel. They listened carefully and heard distantsounds that could not quite be made out, but nothing that seemeddangerous. They slipped through.

  And, through a wide chamber and up a flight of steps, they found theywere in what Burckhardt recognized as the Contro Chemicals plant.

  * * * * *

  Nobody was in sight. By itself, that was not so very odd--theautomatized factory had never had very many persons in it. ButBurckhardt remembered, from his single visit, the endless, ceaselessbusyness of the plant, the valves that opened and closed, the vatsthat emptied themselves and filled themselves and stirred and cookedand chemically tasted the bubbling liquids they held insidethemselves. The plant was never populated, but it was never still.

  Only--now it _was_ still. Except for the distant sounds, there was nobreath of life in it. The captive electronic minds were sending out nocommands; the coils and relays were at rest.

  Burckhardt said, "Come on." Swanson reluctantly followed him throughthe tangled aisles of stainless steel columns and tanks.

  They walked as though they were in the presence of the dead. In a way,they were, for what were the automatons that once had run the factory,if not corpses? The machines were controlled by computers that werereally not computers at all, but the electronic analogues of livingbrains. And if they were turned off, were they not dead? For each hadonce been a human mind.

  Take a master petroleum chemist, infinitely skilled in the separationof crude oil into its fractions. Strap him down, probe into his brainwith searching electronic needles. The machine scans the patterns ofthe mind, translates what it sees into charts and sine waves. Impressthese same waves on a robot computer and you have your chemist. Or athousand copies of your chemist, if you wish, with all of hisknowledge and skill, and no human limitations at all.

  Put a dozen copies of him into a plant and they will run it all,twenty-four hours a day, seven days of every week, never tiring, neveroverlooking anything, never forgetting....

  Swanson stepped up closer to Burckhardt. "I'm scared," he said.

  They were across the room now and the sounds were louder. They werenot machine sounds, but voices; Burckhardt moved cautiously up to adoor and dared to peer around it.

  It was a smaller room, lined with television screens, each one--adozen or more, at least--with a man or woman sitting before it,staring into the screen and dictating notes into a recorder. Theviewers dialed from scene to scene; no two screens ever showed thesame picture.

  The pictures seemed to have little in common. One was a store, where agirl dressed like April Horn was demonstrating home freezers. One wasa series of shots of kitchens. Burckhardt caught a glimpse of whatlooked like the cigar stand in his office building.

  It was baffling and Burckhardt would have loved to stand there andpuzzle it out, but it was too busy a place. There was the chance thatsomeone would look their
way or walk out and find them.

  * * * * *

  They found another room. This one was empty. It was an office, largeand sumptuous. It had a desk, littered with papers. Burckhardt staredat them, briefly at first--then, as the words on one of them caughthis attention, with incredulous fascination.

  He snatched up the topmost sheet, scanned it, and another, whileSwanson was frenziedly searching through the drawers.

  Burckhardt swore unbelievingly and dropped the papers to the desk.

  Swanson, hardly noticing, yelped with delight: "Look!" He dragged agun from the desk. "And it's loaded, too!"

  Burckhardt stared at him blankly, trying to assimilate what he hadread. Then, as he realized what Swanson had said, Burckhardt's eyessparked. "Good man!" he cried. "We'll take it. We're