I asked, “If Peter’s here, who let him in?”

“Nobody. He found a way down one of the old ventilation shafts.”

I remembered the ancient, disused chimney; yes, I realized, if you knew what you were doing, it wouldn’t be so hard to work your way in. I laughed. “Peter’s a bit tubby for a potholer.”

She stood close to me. I smelled something of the animal stink of the Crypt about her. Her fists were clenched, her body rigid, every muscle suffused with anger. “You think this is funny? Do you? Funny? He isn’t one of us. He has nothing to do with the Order. And he’s here because of you.”

“I didn’t tell him where the shaft outlets were. I don’t even know myself.”

“Evidently you told him enough for him to work it out. You betrayed our trust, George. You betrayed my trust. I took you into my home. I showed you its treasures. And you told an outsider. Perhaps you aren’t fit to join us after all.”

Her cold, angry rejection was powerful. It hurt badly to feel such exclusion, despite my ambiguous feelings about the whole setup.

“Rosa, I know Peter. Outsider or not he’s an old friend who was good to Dad in his final years. He is — odd. Obsessive, eccentric. He has big ideas. But even if it’s true he’s broken in here he’s harmless.”

“Harmless. Really.” Rosa walked behind the marble desk to the guard’s PC. It took her a couple of minutes to find what she wanted. She swiveled the screen on its mount to show me. “This is an Interpol report. Posted by the FBI.” Illustrated by small, grainy photographs, it was a report of an explosion at a university science lab in San Jose, California. The lab had been devoted to something called “geometric optics.” The blast had destroyed the building and killed three people, including a cleaner and the head of the facility. The FBI appeared convinced it was some kind of sabotage. In the corner of the image the FBI had posted two photographs, of suspects they associated with the incident.

One of them was, indubitably, Peter’s face.

I stood back. “Shit.”

“Our face-recognition software pulled this up not five minutes after we got our first clear shot of him.”

“It has to be a mistake. Peter’s an eccentric, not a criminal. I can’t believe he’d have anything to do with an incident like this.”

Rosa briskly spun the screen back. “Tell it to the FBI. And in the meantime, this ‘harmless’ friend, this suspected bomber, this murderer, is holed up inside the Crypt — and you led him here.”

“What do you expect me to do?”

“Come down there with me and get him out.”

I hesitated. I dreaded walking deeper into this mess. But I knew I had no choice.

Rosa walked me to the high-speed elevators that would take us back into the downbelow. The doors slid open with a pneumatic sigh.

Once more I was swallowed up.

I stepped out into the now familiar crush.

Even as we hurried toward the scene of the crisis, I lifted my head and took deep breaths. The air was clammy and shallow, and my lungs pulled, trying to extract oxygen. But there was that powerful animal stink again, the musk of sweat and piss, of blood and milk, so suffocating, and yet somehow so exhilarating.

I was full of doubts about the Order, full of conflicting emotions. I had listened to Peter’s extraordinary arguments about eusociality and hives and Coalescents, a new form of humanity. And above all, stuck in my head, was the image of Lucia, a fifteen-year-old tortured by the exploitation of her fecundity by — well, by somebody in this place, for some purpose, not her own. But for all that it was good to be back. I belonged here: walking down these dense corridors again, I seemed to feel it on some deep cellular level. However the Order was sending me signals, through body language or chimp grunts or scent or whatever the hell, it was certainly getting through.

But the Crypt felt different today.

All those ageless female faces, and a few male, all with their smoky gray eyes, peered at me uncertainly, eyes wide, mouths downturned. I was sure that few of them would know anything about what was going on, but they picked up their cues from Rosa, and then from each other, and as we walked they all unthinkingly flinched away from me. That silent rejection hurt.

But even through this self-pitying ache, I noticed the Crypt was quiet : people spoke, but softly, leaning to whisper in each others’ ears. They even walked quietly, their feet padding gently on the floor. I listened for the hum of generators, the hiss and low roar of the air-conditioning systems, but could hear nothing.

“Silent running,” I said to Rosa.

“What do you mean?”

“Just like a submarine, trying to evade the sonar of the surface ships. We’re in a great, static, underground submarine …”

It struck me then that the Order, whatever its powers and wealth, being stuck immovably in this Crypt, this hole in the ground, was terribly vulnerable. No wonder Rosa had reacted so strongly to Peter’s incursion. For the Crypt to be revealed was about the worst thing that could happen, because once exposed it would stay exposed. The silent running must be instinctive, I thought, a reaction bred in over generations. A great wave of fear and despondency must have rippled out through the tight-packed, touching, gossiping members of the Order, a wave of alarm but not of information, a wave that left silence and caution where it passed.

We descended to Level 2 and hurried past the great galleries of hospital wards and dormitories. Eventually we began to pass through quieter, darker corridors. I sensed we were moving out of the core of the sprawling complex, reaching areas I hadn’t seen before. Perhaps the ventilation shaft Peter had used was old, long abandoned, unguarded.

At last we came to a wall, not of concrete or interior partition, but of tufa, honest, solid lava. I ran my hand along the wall. I felt oddly reassured to think that I wasn’t in the middle of things anymore — that beyond my hand there were no more galleries and chambers, no more people, nothing but a tremendous mass of patient, silent rock.

A knot of people stood before a cleft in the rock wall, all Order members. The lighting here, coming from fluorescent lamps bolted crudely to the tufa wall, was sparse and dim, and as they watched us approach, their faces, all so similar, seemed to float, disembodied, in the gloom. I recognized none of them. There were ten of them — only one was a man — but they were all tall and hefty looking inside their smocks. They were here for physical work, I thought, perhaps to wrestle Peter to the ground.

And they were old, I realized with a shock; with crow’s-feet eyes and sunken cheeks, they all showed far more visible signs of aging than I had seen in the Crypt before. Uneasily I remembered Peter’s talk of aging ant warriors, of elderly mole rats sacrificed to the jackals; it was another unwelcome parallel.

Rosa spoke briskly to these guardians and came back to me. “He’s still in there.”

“Where?”

She jerked her thumb at the cleft in the rock.

I moved past her to take a look. The cleft was a crack in the tufa, barely wide enough for me to have squeezed into sideways. It looked as if it had been caused by a mild earthquake, and then widened by seeping water. The glow from the wall-mounted lamps didn’t penetrate very far, and I cupped my hands over my eyes, peering into silent blackness.

Suddenly light flared in my face. I fell back, rubbing my eyes. “ Ow. Shit.”

A sardonic voice, made hollow by echoes, came drifting out of the cleft. “You took your time.”