The iron sconces set into the canal masonry held pine-pitch torches that had burned steadily through three hours of sapper assault. They did not gutter in the river damp; the resin was thick, blended with mutton tallow to resist the subterranean drafts that swirled through the storm flumes.
Now, without a whisper of wind to disturb the humid trench, every flame tilted sideways.
The tongues of orange fire leaned toward the eastern wall at a flat, impossible slant, pinned at forty-five degrees like pennants caught in a gale. The greasy black smoke that should have drifted toward the ceiling grates flattened against the granite blocks in thin, parallel ribbons, racing toward the distant core chamber as if drawn by an invisible vacuum.
Jon watched the fire. He had witnessed this phenomenon twice before, during the frantic ends of the third and fifth returns. It was not a physical draft. The air in the conduit remained dead and heavy, thick with the stench of scorched limestone, wet wool, and ancient stagnant silt. The leaning flame was temporal shear—the localized warping of causality as the Hearth Nail reached critical saturation, pulling the seconds toward itself before the fabric of the hour tore open.
