Bellamy Cordell

Callow Arch was raised to outlast empires and winter spates: a five-story limestone fortress seated on a sheer rock needle in the throat of an impassable river gorge. But when twin flash floods smash both timber approach spans into splinters in a single afternoon, the surviving garrison finds itself marooned above sixty feet of boiling cataract. Winch-tender Garret Vane watches the churning brown torrent turn milky and fever-warm, while mason Norris Claver discovers that the ancient mortar between the foundation blocks is weeping sweet water and softening into living silt. The river goddess has revoked her pact of stone. As damp river-reeds take root in salted grain barrels and sentries wake with cold river stones wedged beneath their tongues, the water begins to mount the spiral staircases, claiming the living as suitors for the depths below.

Every citizen of Harrowport knows the sound of survival: the deafening roar of the perimeter steam sirens, whose acoustic shockwaves shatter the occult horrors creeping from the salt marshes. Della Vinson doesn't hear the sirens—years on the high-pressure boiler gang took her hearing—she feels them in the iron decking beneath her boots. But when the horn manifold's pressure plunges during the highest fog-tide of the century, Della discovers saboteurs have slaughtered her crew and jammed the steam conduits. With the defensive sound wall failing and amphibious hulks tearing through the outer sea-gates, Della is the only technician left on the high catwalks. To save the lower harbor, she must superheat a fractured boiler and fire the sirens past their breaking point, even if the blast shatters her bones.