"And over there," Lise said, pointing. Another shaped object, this one resembling a gear out of an old mechanical clock. It, too, crumbled when he touched it.

Tyrell went to the staff room and came back with a flashlight. When he played the beam over the tablecloth at a raking angle it showed up a number of these objects, if you could call them "objects"—the faintly structured remains of things that appeared to have been manufactured. There was a tube about a centimeter long, perfectly smooth; another about the same size, but knobbed like a length of spine from some small animal, a mouse, say. There was a six-pronged thorn; there was a disk with miniature, crumbling spokes, like a bicycle wheel; there was a beveled ring. Some of these things glinted with a faint remnant light.

"All burned," Lise observed.

Burned or otherwise decomposed. But how could something so completely cremated remain even partially intact after falling from the sky? What had these things been made of?

Also present in the ashfall were a few luminous specks. Turk hovered his hand over one of them.

"Careful," Lise said.

"It's not hot. It's not even warm."

"Could be, I don't know, radioactive."

"Could be." If so, it was another doomsday scenario. Everyone outside was inhaling this stuff. Everyone inside soon would be. None of these buildings was airtight, none of them filtered its air.

"You learning anything from this?" Tyrell asked. Turk stood up and brushed his hands.

"Yeah. I'm learning that I know even less than I thought I did."

* * * * *

He accepted Lise's offer of temporary shelter. They borrowed spare kitchen clothing from Tyrell, chef's jackets to protect their clothes from the falling ash, and they shuffled as fast as they could across the gray dunes in the parking lot to Lise's car. The ash cloud had turned the sky dark, obscured the meteor shower, dimmed the streetlights.

Lise drove a Chinese car, smaller than Turk's vehicle but newer and probably more reliable. He shook himself off as he climbed into the shotgun seat.

She steered the vehicle out the back exit from the parking lot onto a narrow but less crowded avenue that connected Rue de Madagascar to Rue Abbas. She maneuvered the car with a kind of cautious grace, nursing it over the accumulations of dust, and Turk let her concentrate on her driving. But as the traffic slowed she said, "You think this is connected with the meteor shower?"

"It seems like more than a coincidence. But who knows."

"This is definitely not volcanic ash."

"Guess not."

"It could have come from outside the atmosphere."

"Could have, I guess."

"So it might be connected to the Hypothetical."