Duncan: “Where the eastern approaches of the Kalif’s empire fade into the mountains no man can conquer, the ruined fortress of Zamilon keeps watch over time and the stars. Within the fortress … Truffidian monks guard the last true page of Tonsure’s famous journal.”

Below the battlements, the great hulking shadows of some kind of machinery. Engines of war flanking a wide road that led to a huge door. Looked like it was made half of volcanic rock and half of charred book cover. Set in the door, a smaller door, and a small door set into that one.

Painted and carved into every surface, radiating outward, the symbol from the scrap of paper:

Finch pointed to it. “What’s that?”

“It’s part of how we travel through the doors. Part of the … mechanism. But it means something different to the gray caps. It doesn’t work the same way for us as for them. Thankfully.”

Turned to the scene beyond the battlements. Furtive movement out there. Occluding the fires at times. A suggestion of long, wide limbs. Of misshapen heads.

“And all of that?”

“Those are the fires of enemy camps. Not gray caps. Not human. Something else. They don’t know what to make of us. And we don’t know what to make of them. But we have to hold this positison. Do you want to know why?”

Felt again like he was falling. “I’m not sure.”

The Lady in Blue pulled him around. Held him by the shoulders. A viselike grip. An almost inhuman strength. He understood now, on a physical level, how she had held on, and kept holding on, all this time.

“You don’t have that luxury, James Scott Crossley. That out there is nothing. It’s just the latest thing to make us falter, to make us doubt ourselves.” She released him. “When we started out, we didn’t really understand. We had to learn fast.”

“You read Samuel Tonsure’s journal?”

“That and other things. Shriek’s books after we found him.”

“And you learned about Zamilon?”

“Sometimes by hard-earned experience. But now we know: Zamilon is a nexus for the doors. It exists in our world, but it also exists in many other worlds simultaneously.”

“And Duncan needed to go through it for his mission? He was on a mission for you?”

“Yes. But he’s unpredictable. We think he went somewhere he shouldn’t have. Triggered a trap. I’m not sure we’ll ever know what went wrong unless Shriek chooses to tell us.”

“So it’s dangerous to travel through the doors?”

She stared up at the wash of stars. “It can be. We only use doors leading from or to Zamilon. Anything else has resulted in disaster. We don’t know why. But Duncan has no such constraint…”