She focused her attention on the sound of Isaac's breathing, thinking how strange life must have been for Isaac, raised motherless—Mrs. Rebka had been something less than a mother—and fatherless—unless you counted Dr. Dvali's sinister hoverings—but indifferent, by all accounts, to affection. A difficult, refractory child.

She had overheard a little of Sulean Moi's argument with Dr. Dvali earlier today. It had raised uneasy questions in her mind.

The Martian woman was right, of course. Dr. Dvali and Mrs. Rebka weren't scientists, studying the Hypothetical by unconventional means. They were on a pilgrimage. And at the end of it they expected something holy, something redemptive.

The same longing—years and years ago now—had carried her almost to her death. Diane had wrapped herself in her first husband's faith, and he had taken her to a religious retreat where she contracted an illness that nearly killed her. The cure had been her conversion to what the Martian Wun Ngo Wen had called the Fourth state, the adulthood beyond adulthood.

She thought she had left that longing behind her when she became a Fourth. It was as if, after the longevity treatment, something cool and methodically rational had risen up and taken control of her life.

Something soothing, if a little deadening. No more reckless storming of Heaven. She had lived a steady, useful life.

Could she have been wrong, though, about how much she had left behind and how much she still carried with her, unsuspected? When the lines had intersected on the map, the triangulation of Isaac's urges, Diane had felt a familiar longing for the first time in… oh, many years.

She felt it again when she found out that Isaac could gain access to the memories of a long-dead Martian child he had never known.

The Hypotheticals had remembered Esh, Diane thought.

What else might the Hypotheticals have remembered?

Her brother Jason had died in a state of attempted communion with the Hypotheticals. Did they remember that! Did they in fact remember Jason?

And if she asked, would Isaac speak with Jason's voice?

She sat upright, almost guiltily, when the building began to tremble and shake. Fortifications breached, she thought dazedly: the walls of Heaven tumbling down.

* * * * *

By the time Turk managed to light a candle, the shaking had stopped.

The old Chinese lady was right, he thought. Earthquakes!

He turned back to Lise, who sat up in bed with the blanket pooled around her waist. He said, "You okay? It's just a tremor."

"Promise we won't stop," she said.

Turk blinked. Her skin by candlelight was pale, unearthly. "Stop?"

"When they get where they're going," and he understood by a toss of her head that she meant the Fourths, "we don't stop, right? We keep on heading for the west coast? Like you said?"

"Of course. What are you worried about? This was just a tremor, Lise. You lived in California, you must have felt little quakes like that."