For detective Joe Lombardi, when a body is discovered dangling beneath the Carroll Street Bridge, the first place he turns to for answers is the nearby canal. With its long history of pollution and neglect, the canal has gained a dubious reputation for ruining people's lives—Joe's included. But to Joe's younger partner, Alan D'Angelo, Joe is little more than a liability, a chain-smoking failure who stands in the way of a much-coveted promotion.
Determined to turn the occasion of their investigation to his favor, Alan vows to end Joe's career by beating him to the killer and currying favor with their new boss. But when it comes to the canal nothing is ever what it seems: as Joe and Alan set out to catch their killer, they're about to stumble across an unspeakable secret, one that's waiting for them just beneath the water's dark surface...