Sulean had never made a secret of it. The story had spread among these Terrestrial Fourths—especially those, like Dvali, who were obsessed with the Hypotheticals. She nodded.

"A child like Isaac," Mrs. Rebka said.

"In some ways like him. A boy. He was Isaac's age when he—"

"When he died."

"Yes."

"Died of his… condition?"

Sulean didn't answer immediately. She hated calling up these memories, instructive as they inevitably were. "He died in the desert." A different desert. The Martian desert. "He was trying to find his way, but he got lost." She closed her eyes. Behind her eyelids the world was an infinite redness, thanks to this insufferably bright sunlight. "I would have stopped you if I could. You know that. But I came too late, and you were all very clever about concealing yourselves. Now I'm as helpless as you are, Mrs. Rebka."

"I won't let you hurt him." The fervor in Mrs. Rebka's voice was as startling as the accusation.

"I wouldn't do anything to harm him!"

"Possibly not. But I think, on some level, you're frightened of him."

"Mrs. Rebka, have you misunderstood so completely? Of course I'm afraid of him! Aren't you?"

Mrs. Rebka didn't answer, only stood up and walked slowly back into the compound.

That night Isaac was still feverish and was confined to his room. Sulean lay awake in her own room, gazing past the sand-scuffed windowpane at the stars.

At the Hypotheticals, to use that wonderfully ambiguous name bestowed upon them by English-speaking people. They had been called that even before their existence was well-established: the hypothetical entities who had enclosed the Earth in a strange temporal barrier, so that a million years might pass while a man walked his dog or a woman brushed her hair. They were a network of self-reproducing semibiological machines distributed throughout the galaxy. They intervened in human affairs, and perhaps the affairs of innumerable other sentient civilizations, for reasons not well-understood. Or for no reason at all.

She was looking at them, though they were of course invisible. They permeated the night sky. They contained worlds. They were everywhere.

Beyond that, what could one say? A network so vast it spanned a galaxy was indistinguishable from a natural force. It could not be bargained with. It could not even be spoken to. It interacted with humanity over inhuman spans of time. Its words were decades and its conversations were indistinguishable from the process of evolution.

Did it think, in any meaningful sense? Did it wonder, did it argue with itself, did it fabricate ideas and act on them? Was it an entity, in other words, or just a huge and complex process?