And then on the screen she saw the wall as the camera panned out into the desert. There—the red glass wavy wall. It was new and sharp and the sand beyond it was seared and blackened and in places sprayed with blood. The wall marked the boundaries of the rubble as if the sand had risen up…

…in a giant “splash.” As if the City had been set down intact, like the house in The Wizard of Oz.

The ruined city she was seeing was this city or, at least, its predecessor. And the planet where this cataclysm had taken place was this planet.

The man was back, his voice rising and falling with emotion. He tried to explain what had gone wrong, but it didn’t sound like he really knew. He knew only that they had turned on the machine, they had turned it on, and at first it had all gone well, but then at nine hours, twenty-three minutes, and sixteen seconds after throwing the switch…

Idiots! Jill thought, furious. They made a weapon! They made a negative one pulse machine. And it…it… it exploded. Or… for god’s sake!

Her hands were clammy. She felt dizzy. She was going to pass out; her consciousness was slipping away like quicksilver. It was the musty air in this place, those ghastly images.

She groped around in the dark for a chair, but her hands found nothing. The man was saying that the machine had been shut down and it must never, ever be turned on again, at least not until they had found a way to reverse the effect, to get home. But Jill just kept thinking, They made a weapon; they made a goddamn weapon!

The dark was stifling, suffocating, and she wanted out. The slightly restrained hysteria of the man on the tape was getting to her; it was sinking hooks into her that would probably never come out. But if she turned around now and tried to grope her way through the dark toward the door she might not find it in her panic—she might miss the door and spend hours wandering this vast machine in the dark!

She made herself sink to the floor and put her head between her knees. The air in here was so bad, it was like breathing the air of a coffin. But her nausea did slowly fade. As her head cleared, she kept hearing the man repeating over and over, We only wanted to help, and those words, and a dozen other hints in his long speech, finally clicked.

Dear God. Oh dear God. This isn’t a negative one pulse machine. It wasn’t created as a weapon. This machine was made to send a one pulse.

Jill gasped hugely, her head coming up, eyes riveted on the screen. It was true. She had just told Nate about her idea, that they could push the one pulse instead of the negative one, make Earth a living paradise. She thought she would be a god, a legend, an immortal for inventing such a thing, that she would change humanity’s lot forever. And this very machine was just that—a “benevolent atmosphere producer”—and the aliens had built it. And it had done that.

“Get up now,” a voice said.

She looked around, confused. For a moment she thought it was another television speaking. But the source of the voice stepped in front of the monitor and the light of the screen gave it form. It was an alien, a male, one of the tall, pale creatures they’d seen several times on this planet. He switched the button to end the video transmission.

“I am becoming ill on this air,” the alien said flatly. “And I cannot leave you alone inside the machine. You must exit at once.”

Jill didn’t move, too amazed to connect these words with herself.

“Please get up and leave the machine,” the alien repeated in a higher pitch, motioning his long fingers.

She stood obediently and began to move back the way she had come. She didn’t feel the alien brush past her, but in a few minutes she heard the door up ahead of her open and saw the light of the outer chamber. The alien was at the door, holding it open. She slipped through, anxious to keep her distance from the thing, and she didn’t turn around until she was a good twenty feet away. When she did turn, the alien was standing at the machine with his arms at his sides, face blank.

He was tall and stick-thin, as all the males were. It was startling to have those huge gelatinous black eyes actually focused on her. He spoke: “The probability is low that you would be able to start the machine, but I prefer that you not enter it again.”

“You can see me,” Jill said.

“Obviously.”

It was spoken in such a dry, factual way that it was almost funny. The weirdness of the situation—actually talking to one of these creatures—suddenly impressed itself on Jill and for a moment pushed everything else from her mind, even the machine.

“Most of the aliens on this planet don’t seem to be able to see us. At least, they have not acknowledged us in any way.”

“They do not see you because they do not expect you to be there. I, myself, saw you and the male some days ago. I have been analyzing the benefit of contact and had decided against it. It was only to ask you to leave the machine that I spoke.”

“What do you mean, they do not expect us to be there?”

He answered patiently, as if talking to a moron, “The brains of most species are designed to interpret energy patterns into three-dimensional solid matter. If an energy pattern is not anticipated it may be discarded by the filter as random noise.”

Jill gave this some thought. She herself was certainly capable of filtering out an awful lot when she was preoccupied, even large expected things, like, say, Dick Chalmers. “But we saw you. Are your brains so different from ours?”

The alien did a slow double blink before answering. “Your brain specifically is much like ours. You were in a strange place and therefore were expecting to receive unusual patterns. The same is not true for the ones who live here. I, myself, was able to see you because of the nature of my work. I have been programmed to think about other species. I have diagrams of many species and that is why my brain is familiar with the concept.”

“Oh.” Jill thought it could take the rest of her life just to understand everything he’d just said.

“However, one thing of interest I have observed while studying you: the male’s brain is more different from ours. When you and the male separated I made the calculation to follow you for this reason. I do not understand the brain of the male. You are female—this is true?”

“Yes.”

“Curious,” the alien said flatly.

Despite his choice of vocabulary, there seemed to be no emotion in him, not surprise and not much curiosity. He stood motionless, staring at her, his translucent lids rising and falling over that jelly coating on his eyes. It was a little gross.

“You don’t have many females, do you?” Jill tried. “Is that what’s wrong with your planet?”

“Wrong?”

“The City is almost deserted.”

“You refer to the fact that our species will soon cease to exist. We have come to see this as an inevitability. As machines become obsolete, so do species. I am a postspecies specialist. It is my job to prepare for our extinction, for those who may come.”

He said it so matter-of-factly. It was depressing, but Jill couldn’t help thinking that if they were expecting someone, there would be space travel, perhaps even rescue. “Who are ‘those who may come’?”

“Unknown. The statistics are high that others will come in time. Your appearance was far sooner than predicted. However, I have reached the conclusion that you are not proper recipients. Someday someone will come who will be the appropriate vessels for our legacy.”

“Your legacy? You mean your technology? Your knowledge?”

“Yes.”

“But I’d like very much to learn what you know!”

“Are you and the male breeders? Can you repopulate this planet?”

“No,” she admitted. “Our gene pool couldn’t survive without other human beings to breed with.”