Black Water Vault

Forty feet below the drowned boulevards of Nouar-el-Bahr, municipal saturation diver Tidjani earns his living clearing the delta city's subterranean flood-tunnels. But when a record hurricane slams the coast, Sump Turbine 4 seizes completely, threatening to back up billions of gallons of toxic sludge into the densely packed slums above. Diving blind into zero-visibility runoff, Tidjani discovers the intake isn't choked with timber and debris—it's blocked by a writhing, multi-jawed occult biomass anchoring itself to the sluice gates. Armed with a pneumatic cutter and a rapidly draining air rig, Tidjani must sever the creature from the turbine shaft while dodging the armed saboteurs who seeded the monster into the sewer system.