There was an obvious question Lise had been wanting to ask since they arrived at the Fourth compound, and since no one else had anything to say—and because the noise of the windshield wipers scraping dust across glass was driving her slightly crazy—she drew a breath and asked, "Is Isaacs mother still alive?"

"Yes," Mrs. Rebka said.

Lise turned to face her. "Are you his mother?"

"I am," Mrs. Rebka said.

What do you see, Isaac?

Much later, as he was waking up from the sleep they had injected into him, Isaac pondered the question.

Mrs. Rebka was the one who had asked it. He tried to formulate an answer before the pain came back and stole his words. But the question was hard to answer because he was having a hard time seeing anything at all. He was aware of the vehicle and the people in it, the ash falling beyond the windows, but they all seemed vague and unreal. Was it daytime yet? But now the car had stopped, and before he answered Mrs. Rebka's question he asked one of his own: "Where are we?"

Up front, the man named Turk Findley said, "Little town called Bustee. We might be staying here a while."

Outside there were small buildings visible through the fog of dust. He could see them plainly enough. But that wasn't what Mrs. Rebka had meant by her question.

"Isaac? Can you walk?"

Yes, he could, for now, though the sedative was wearing off and the blade of the world was beginning to draw blood again. He climbed out of the car with one hand on Mrs. Rebka's arm. Dust sifted across his face. The dust smelled like something burned. Mrs. Rebka steered him toward the nearest small building, which was one wing of a motel. Isaac heard Turk say he had rented the last available room, for more money than it was worth. Lots of people were sheltering in Bustee tonight, Turk said.

Then he was inside, on a bed, on his back, and the air was less dusty, though it still stank, and Mrs. Rebka brought a fresh cloth and began to dab the grime from his face. "Isaac," she said again gently, "what are you looking at? What do you see?"

Because he kept turning his head in one direction—west, of course—and staring.

What did he see?

"A light."

"Here in the room?"

No. "A long way away. Farther than the horizon."

"But you can see it from here? You can see it through the walls?"

He nodded.

"What does it look like?"

Many words crowded Isaac's mind, many answers. A fire in a faraway place. An explosion. Sunrise. Sunset. The place where the stars fall and burn in their eagerness to live. And the thing deep underground that knows and welcomes them.

But what he said was simply, truthfully, "I don't know."

Only Turk had been to Bustee before. The name, he said, was derived from a Hindi word for "slum." It wasn't a slum, but it was a greasy little road town on the edge of the Rub al-Khali, catering to traffic along the northernmost route to and from the oil lands. Cinderblock buildings and a few timber-framed houses; a store that sold tire gauges, maps and compasses, sunblock, cheap novels, disposable phones. Three gas stations and four restaurants.

None of which Lise could see from the window of the motel room. The ashfall sifted down in gray, stinking curtains. Power lines down or transformers shorted by dust, she guessed, and repairs wouldn't be quick, not out here in low-priority-land. It was a miracle they had made it here at all, even in their big all-terrain all-weather vehicle. Someone from the motel office knocked at the door and handed out flashlights and a warning not to attempt candles or any kind of open flame. But the Fourths had packed their own flashlights, and there was nothing to see anyway, only dingy walls and patchwork wallpaper. Lise kept a flashlight at hand for navigating her way to the bathroom when the need arose.

The boy Isaac slept, driven more by exhaustion than sedatives now, Lise guessed. The adults had huddled for conversation. Dr. Dvali was speculating about the ashfall in his persuasive and gently-modulated voice. "It might be a cyclical event. There's evidence in the geological record—this was some of your father's work, Miss Adams, though we never knew how to interpret it. Very thin ash layers compressed into the rock at intervals of ten thousand years or so."

"What does that mean," Turk asked, "it happens every ten thousand years? Everything gets buried in ash?"

"Not everything. Not everywhere. You find evidence of it mainly in the far west."

"Wouldn't it have to be a pretty thick layer to leave traces like that?"

"Thick, or persistent over a long period of time."

"Because these buildings aren't built to hold up anything much more than their own weight."

Roofs crushed, dust entombing the survivors: a cold Pompeii, Lise thought. That was chilling. But she had another thought. She said, "And Isaac—is the dustfall connected with what's happening to Isaac?"

Sulean Moi gave her a sad look. "Of course it is," she said.

Isaac understood it best in his dreams, where knowledge was rendered in wordless shapes and colors and textures.

In his dreams, planets and species arose like vagrant thoughts, were dismissed or committed to memory, evolved as thoughts evolved. His sleeping mind worked the way the universe worked—how could it be otherwise?

Half-heard phrases filtered into his floating awareness. Ten thousand years. The dust had fallen before, ten thousand years before and ten thousand years before that. Vast structures seeded space with their residue, feeding cyclical processes that turned and turned like faceted diamonds. The dust fell in the west because the west was calling it, as the west called Isaac. This planet wasn't Earth. It was older, it existed in an older universe, old things lived inside it. Things lived inside it: things that were not mindful but listened and spoke and pulsed in slow, millennial rhythms.

He could hear their voices. Some were close to him. Closer than they had ever been before.

The groan of the hotel's stressed beams and timbers continued after dusk and through the night—management sent a crew up to shovel the roof—but the ashfall tapered off, and by dawn the air had cleared to a gritty semitransparency. Lise had fallen asleep despite her best efforts to stay awake, curled on a foam mattress with the stink of the dust in her nostrils and sweat streaking her face.

She was the last to wake. She opened her eyes and saw that the Fourths were up and had gathered at the rooms two windows. The light coming in was less bright than a rainy autumn glow, but it was more than she had dared hope for while the dust was still falling.

She sat up. She was wearing yesterdays clothes and her skin was encrusted with yesterday's dirt. Also her throat. Turk had noticed her movement; he handed her a bottle of water and she gulped it gratefully. "What time is it?"

"About eight." Eight o'clock by the long Equatorian reckoning of the hours. "Sun's been up for a while now. The dust stopped falling but it's still settling. A lot of fine powder in the air."

"How's Isaac?"

"He's not screaming, anyway. We're okay… but you might want to take a look outside."

Mrs. Rebka stepped back to tend to Isaac and allowed Lise to take her place at the window. Lise looked outside reluctantly.

But there seemed to be nothing unexpected. Just a road drifted over with ash, the same road they had crept along yesterday, pushing their vehicle to the limit of its endurance. The car was where they had left it, dust duned on the windward side. Its webbed steel wheels were still dilated, as big as the tires on the industrial rigs parked in sheltering rows beyond it. The daylight was dim and gritty, but she could see all the way to the gas station some hundred or so yards to the south. The road was empty of pedestrians, but other faces peered from other windows. Nothing moved.