“Do you remember when one of the vaulted chambers collapsed?”

“No,” she said irritably. “I don’t. Do you remember the time Ann and Sax had that big argument about the terraforming?”

“No,” Michel said with a sigh, “I can’t say I do.”

They could go back and forth like that for a long time, until it seemed they had lived in completely different Underhills. When they both remembered an event, it was cause for cheer. All the First Hundred’s memories were growing spotty, Michel had noticed, and it seemed to him that most of them recalled their childhoods on Earth better than they did their first years on Mars. Oh, they remembered their own biggest events, and the general shape of the story; but the little incidents that somehow stuck in mind were different for everyone. Memory retention and recollection were getting to be big clinical and theoretical problems in psychology, exacerbated by the unprecedented longevities now being achieved. Michel had read some of the literature on it from time to time, and though he had long ago given up the clinical practice of therapy, he still asked questions of his old comrades in a kind of informal experiment, as he did now with Maya: Do you remember this, do you remember that? No, no, no. What do you remember?

The way Nadia bossed us around, Maya said, which made him smile. The way the bamboo floors felt underfoot. And do you remember the time she screamed at the alchemists? Why no! he said. On and on it went, until it seemed that the private Underhills they inhabited were separate universes, Riemannian spaces that intersected each other only at the plane at infinity, each of them meanwhile wandering in the long reach of his or her own idiocosmos.

“I hardly remember any of it,” Maya said at last, darkly. “I can still barely stand to think of John. And Frank too. I try not to. And then something will trigger something, and I’ll be lost to everything else while I remember it. Those kinds of memories are as intense as if what you remember only happened an hour before! Or as if it were happening again.” She shuddered under his hands. “I hate them. Do you know what I mean?”

“Of course. Mémoire involuntaire. But I remember also that the very same thing happened to me when we were living in Underhill. So it isn’t just getting old.”

“No. It’s life. What we can’t forget. Still, I can hardly look at Kasei . . .”

“I know. Those children are strange. Hiroko is strange.”

“She is. But were you happy, then? After you left with her?”