They went through a door, and passed down another corridor. It was colder here, and darker, lit only by a string of dangling bulbs.

Rosa said as they walked, “Ten thousand people live here, in the Crypt. Every year, about one percent of us die—some accidents and illnesses, mostly old age. That’s a hundred a year. That’s how many have to be replaced. You said it yourself: the Order must be renewed. Has it occurred to you to wonder how?”

Lucia frowned. “There must be a hundred babies a year, then. To maintain the numbers.”

“That’s right. Just as we saw in the nursery. The future of the Order: every year a hundred warm bodies are passed into the great processing machine of the Crypt at one end, and a hundred cold ones carried out the other. Eh?”

Lucia shuddered. “That’s a horrible thing to say.”

“But accurate enough. All right. But where do the babies come from, Lucia?”

Lucia, uncomfortable, said, “The matres.”

“That’s right. The matres, the mothers of us all. Lucia, you know that the Order is very old. Once the Order was small, and there were only three matres—like the three ancient goddesses in this alcove. But the Order grew, and we needed more babies, and the matres had to become nine, three times three. And then the Order grew again, and the nine became twenty-seven, three by three by three . . .”

It didn’t seem at all strange to Lucia that to keep up an output of a hundred babies each of those twenty-seven must produce three or four babies each, every year.

They came to a little alcove, carved into the wall. In the alcove, behind a thick slab of glass, stood three tiny statues, grimy with age, worn with much handling. They looked like women, but they all wore hooded cloaks. Perhaps they were figures of Befana, Lucia thought.

Rosa touched the glass. “This is bulletproof . . . These are the first matres, the symbolic heart of the Order—just as the twenty-seven flesh-and-blood matres are its wombs.

“But soon, the twenty-seven will become twenty-six. Maria Ludovica is not, in fact, the oldest of the matres, but she is the frailest. And Maria is dying, Lucia.” Rosa’s eyes seemed huge in the dark. “The last decade, as Maria has weakened, has been a time of turmoil, and more girls like you have emerged—who have become mature, I mean. It is the way of things. Soon somebody must replace Maria. The twenty-seven must be restored.”

“You’re talking about me,” Lucia whispered.

“It has taken me some time to convince certain others that you are the right candidate.” Rosa seemed proud, as if she had won some victory.