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.”