The sound through the copper channel was no longer a gentle metal ringing. It had become an urgent, sharp percussion that shook through Tomas Reed’s fingers like electric current. CLINK... TOCK... CLINK. Eighty feet above, in the coal cellar, Nessa Vale was striking the exposed copper collar with the flat head of her surveying hammer. It sent the exact clockwork countdown down the length of the tubing.
Tomas knelt in the rising black water of Bay Fourteen, his boots now underwater past the ankles in greasy, rotten-egg bilge that smelled of dead eels and decomposed leather. His scarred left forearm throbbed with a cold, grinding stiffness beneath the buckled calfskin brace, the gristle pulling tight against the forearm bone. He tightened his grip on his spark-proof bronze cold chisel. He had spent nine years on the canal locks of Bellwether. There, a broken gate-chain could drop forty tons of water on a crew in three seconds. He understood that when an eight-hundred-pound balance weight was tripped, the air trapped inside an air-powered chamber didn’t simply vent—it wildly decompressed.
“Hester, Olla,” Tomas said, his voice flat, low, and perfectly steady in the dim orange twilight of the dying dark-lantern. “Move to the eastern pier. Sit flat on the flat stone slabs with your backs pressed hard against the cut stone stonework. Keep your mouths open and your hands clamped over your ears. When that balance weight drops, the pressure differential between this vault and the outside air will equalize in a…
