“I can’t say any more. But perhaps McLachlan will listen to you. You can encourage him to blow us all up. You can persuade him to walk away.” Of course she was right, I saw, horrified; the decision had to be mine. “Just remember,” she said coldly, “that there is a place for you here. Even now, even after you brought this lunatic into our Crypt. This can be your home, too. If you do anything to harm us, then you will lose that choice, too.”

I seemed to smell the pounds of Semtex Peter had lodged somewhere in the rock, sense the great weight of the subterranean city around me, the thousands of lives it contained.

Behind us Lucia sat quietly on her bench, her baby on her lap; her gaze was fixed on its face, as if she wanted to shut us out, a malevolent world that wanted to use and control her and her child, even those of us motivated to save her—and I couldn’t blame her.

Now it was my turn to do some pacing. I tried to ignore the hammering of my heart, the remote stink of the Crypt, and to think clearly.

Did I agree with Peter?

Peter’s theorizing about hives and eusociality was all very well. But the reality of the Crypt, which I felt in my blood, was a good deal warmer than his hostile analysis, a lot more welcoming. And I wasn’t about to argue with Rosa about the Order’s history, and the work it had done over centuries. Whatever Peter said, I felt I had no more right to close that down than to shut down the Vatican.

And then there was Homo superior.

I had seen for myself that Peter’s “Coalescents” were not like other humans. Perhaps they were a more advanced form; perhaps Rosa was right that we would need the warm, fecund discipline of Order living to survive a difficult future on a crowded Earth. In which case, what right did I have to make decisions about their future? . . . I felt I was losing touch with the world. I drew on the thick, musty air, suddenly longing for a fresh blast of cool oxygen-rich topside atmosphere to clear my head. I was one man, flawed, vulnerable, mortal, woefully ignorant, and these issues escalated above me on every scale. How could I possibly make a decision like this?

For some reason I thought of Linda, my ex-wife. She had always had a lot more common sense than I did. What would Linda say, if she was here?

Look around you, George.

Lucia looked up at me, her eyes full of bewilderment, her body battered by childbirth, her face prematurely lined with pain.