The side-door lock took Zaira longer than the front door had, which gave me hope there might not be magical wards backing it up. She cursed softly once or twice. I bit my lip to keep from telling her to hurry. I glanced around constantly, but the street remained deserted.

Finally, Zaira rose, and the door swung open onto a flight of plain wooden stairs.

“And there it is.” Zaira stepped aside for me to go first. “Just like you said. Maybe you’re not always an idiot.”

“Thanks.” I stepped through the door into the gloomy stairwell. Grime darkened the interior to a hopeless, gritty charcoal. Even with the wall to lean on, by the time I got to the top, my vision swarmed with golden sparks at the edges.

A short hallway brought us to another locked door, which Zaira had open soon enough. No windows shed light within, but I could dimly make out the bulking rectangle of a desk, some shelves and crates—and, along one wall, the low bulk of a winch, and the top of the portcullis grating rising out of the floor.

I hurried over to the winch, but I could barely make out the ropes leading from it, let alone whether any runes or wirework adorned it.

“I need light,” I told Zaira. “Can you go see whether Marcello has another pocket luminary? Or better yet, get one of those oil lamps?”

“All right. But don’t get any idea I’ll fetch and carry for you when this is over.”

I didn’t wait to watch her hurry out, but turned back to the portcullis in the darkness. As my eyes adjusted, I made out something round on the wall behind it—another mirror? And was that spell wire running from it to the portcullis?

My fingertips brushed it in the dark. Yes, and another wire braid ran to the winch. The mirrors below must be linked to this one. When the trap was sprung below, the upstairs mirror received the signal, dropped the portcullis, and activated the seal.

Heavy boots clomped on the stairs. That wasn’t Zaira, unless she’d grown several new legs and gained a few hundred pounds. A flutter of lantern light raced up the stairs ahead of them, throwing wild shadows into the hall.

Hells take it. I hadn’t figured out how to unlock the seal yet. I shoved my satchel behind a crate, hoping at least to hide what I was doing. Then I drew my dagger and faced the door, blood pounding.

Four armed men crested the stairs and approached the door. The foremost held a lantern, its ruddy light picking out gleams from swords and flintlocks. I made out the Bergandon crest pinned to their chests, but their poorly made uniforms didn’t match.