The sound that preceded the surge was not a splash. It was a deep, deep-throated roar that shook through the marrow of Tomas’s bones, like a freight train of quarry boulders tumbling down an iron chute.
In the dark opening of the bypass arch behind the altar, the black water suddenly turned into a foaming, white torrent. A blast wave of high-pressure air blasted out of the underground passage. He carried the smell of fresh mountain clay and crushed shale, blowing out the animal fat candles in the vestry stairhead sixty paces away. The only light leftover in the entire flooded cathedral was the yellow beam of Mirelle’s clockwork dive-lantern. It glowed beneath the swirling foam like an ember trapped in melting ice.
“Tomas!” Sile shouted, his boots sliding through the silt as the current slammed into his knees like an iron beam. “The bypass gate has blown! The whole Black Tarn is emptying into the sump!”
The water level in the choir was rising with terrifying speed—an inch every four seconds. What had been hip-deep water was already surging around Tomas’s waist. It soaked through his leather waistcoat, chilling his chest until his lungs seized in a reflex, gasping burst.
