Rosa seemed to sense that. “You belong here, George,” she said softly. “I’m your sister, remember. If it’s good enough for me . . . Can’t you feel the calm in here? . . .”

I felt the need to cut through this odd seduction. “What about sex?”

“What about it?”

“You’ve a lot of young people here, cooped up together. There must be love affairs—casual flings—” I felt awkward; trying to discuss such issues with my long-lost sister, I was reaching for fifties euphemisms. “Do you let people screw?”

She stared at me in icy disapproval. “First of all,” she said, “it isn’t a question of ‘letting’ people do anything. There is nobody to ‘let’ you, or to stop you come to that. People just know how to behave.”

“How? Who teaches them?”

“Who teaches you to breathe? . . . And anyhow it tends not to be an issue. Most of the men here are gay. Or don’t have an inclination either way. Others usually leave.” She said this as if it were the most usual setup in the world.

It might fit in. Peter, in his long, rambling analyses of what we had learned about the Order, had speculated it might be some kind of heredity cult. Like neuter women, like Pina, gay men could help out with the raising of the fecund ones, the Lucias. But neither class would be any threat to the precious gene pool, because they didn’t contribute to it.

“Okay, but—Rosa, how come most of the people here are women?”

She looked uncomfortable. “Because most people born here are female.”

“Yes, but how? Some kind of genetic engineering? . . . But you were around a long time before anybody even conceived of the notion of a gene. So how do you manage it? What do you do with the excess boys? Do you do what the Spartans did with their baby girls?—”

She stopped and glared at me, suddenly as angry as I had seen her. “We don’t murder here, George. This is a place that gives life, not death.” It was as if I had insulted somebody she loved—as, perhaps, I had.

“Then how?”

“There are more girls than boys. It just happens. You ask a lot of questions, George. But in the Crypt we don’t like questions.”

“Ignorance is strength.”

She glared at me. “If you really understood that, you would understand everything.” She walked on, but her gait was stiff, her shoulders hunched.

We came to an alcove, cut into the rock. Before it a little shrine had been set up, a kind of altar carved of pale marble. Slender pillars no more than three feet tall supported a roof of finely shaped stone. A glass plate had been fixed before it. Rosa paused here, and looked on reverently.

“What’s this?”