Esh was at his liveliest when he was alone with Sulean. They were allowed to leave the station on certain days to explore the nearby desert. They were supervised, of course—an adult was always within sight—but compared to the closeted spaces of the Station this was wild freedom. Bar Kea was formidably dry, but the scarce spring rains sometimes pooled among the rocks, and Sulean delighted in the small creatures that swam in these short-lived ponds. There were tiny fish that encased themselves in hibematory cysts, like seeds, when the water dried, and sprang back to life during the rare rains. She liked to cup the populated water in her hands, Esh watching with silent wonder as the wriggling things slipped between her fingers.

Esh never asked questions, but Sulean pretended he did. At the Station she was always being taught, always being encouraged to listen; alone with Esh she became the teacher, he the rapt and silent audience. Often she would explain to him what she had learned that day or week.

People had not always lived on Mars, she told him one day as they wandered among sunlit, dusty rocks.

Years and centuries ago their ancestors had come from Earth, a planet closer to the sun. You couldn't see Earth directly, because the Hypotheticals had enclosed it in a lightless barrier—but you knew it was there, because it had a moon that circled it.

She mentioned the Hypotheticals (called by Martians Ab-ashken, a word compounded of the root-words for "powerful" and "remote"), cautiously at first, wondering how Esh would react. She knew he was part Hypothetical himself and she didn't want to offend him. But the name provoked no special response, only his usual blank indifference. So Sulean was free to lecture, imagine, dream. Even then the Hypotheticals had fascinated her.

They live among the stars, as far as anyone knows, she told the boy.

Esh, of course, said nothing in return.

They're not exactly animals, they're more like machines, but they grow and reproduce themselves.

They do things for no apparent reason, she told him. They put the Earth inside a slow-time bubble millions of years ago, but no one knows why.

No one has talked to them, she said, unless you have, I suppose, and no one has seen them. But pieces of them fall out of the sky from time to time, and strange things happen…

* * * * *

Pieces of them fall from the sky: this last piece of information caused considerable consternation among Dr. Dvali's Fourths.

Dvali cleared his throat and said, "There's nothing about such an event in the Martian Archives."

"No," Sulean admitted. "Nor did we ever mention it in direct communication with the Earth. Even on Mars it's a rare occurrence—something that happens once every two or three hundred years."

Mrs. Rebka said, "Excuse me, but what happens? I don't understand."