In a submerged London of the future, Detective Harley Stone is on the trail of a serial killer responsible for the death of his partner, a loss that continues to torment him. As he delves deeper into the investigation, Stone uncovers unsettling truths that suggest his quarry may not be human. The pursuit leads him through a dystopian landscape, where the lines between predator and prey blur, forcing him to confront both the deadly figure he seeks and his own haunting past.