There was a sort of mezzanine in the warehouse, a flight of rickety stairs leading upward to what probably had been administrative offices. I walked carefully down the narrow hallway, avoiding both the rats, which couldn’t see me when I shadow walked, and the broken office furniture, which had been piled along the inner wall. A faint red blinking light high up near the ceiling warned of a security camera. I paused in front of the door to the last office, eyeing it carefully. I knew that to normal eyes it would look like a perfectly normal wooden door, equipped with an electronic lock linked to a retina-scan unit attached to the wall next to it. But the door bore things that the casual observer might have missed, such as the illegible words that were apparently etched into the door’s surface.

‘‘Dragon’s bane,’’ I said softly, looking at it carefully from different angles. I’d never seen one before, Magoth (wisely) never having demanded I burgle a dragon, but Aisling had warned me that any treasure Kostya held might be guarded by a bane.

This one looked powerful, glowing gold against the dark wooden door. I sighed, trying to remember what else Aisling had said about it.

‘‘They’re really tricky, and can be deadly if you don’t know what you’re doing,’’ I recalled her saying, leaning close and speaking quickly as Cyrene and Jim approached. ‘‘I went through four demons breaking Fiat’s bane, but honestly, I wouldn’t advise you to mess with anything Kostya has protected with a bane. It’s just bound to be too dangerous.’’

Those words came back to me now as I examined the door for signs of any weakness. There were none. A quick look at the other rooms, locked by conventional means, yielded nothing as well. I climbed out of the window of the room next to the sealed one, moving carefully along the narrow six-inch stone ledge. I had serious doubts that Kostya would be stupid enough to ignore any entrance into his lair, but figured it couldn’t hurt to check.

The window was guarded by not one, but three different security systems, brands I recognized as being nearly impossible to overcome. As I stood plastered against the side of the building, I thought furiously of any means to get into the room. Via the ceiling? From the floor below? Perhaps through the wall of the office next to it? Those and other hopeless ideas were squirreling through my brain when I noticed something odd about the window. . . . One of the panes of glass shimmered slightly in the stiff breeze that was coming off the river.