In a near-future London, where rising sea levels have left much of the city submerged, Detective Harley Stone is on a relentless hunt for a monstrous serial killer. Plagued by nightmares and guilt over his partner's murder, Stone is a hardened cop with little regard for the rules. His investigation leads him through the flooded streets and abandoned buildings, as he pieces together clues pointing to a killer who is more than human. Teaming up with a new partner, Dick Durkin, Stone finds himself constantly at odds with Durkin's methodical approach and scientific mindset.

As their search continues, Stone's girlfriend, Michelle, becomes entangled in the danger. The tension builds as they uncover the killer's gruesome handiwork and bizarre connections to the occult. Stone and Durkin must navigate personal conflicts while confronting a terrifying adversary that defies conventional understanding. The duo's pursuit is marked by chilling encounters, intense action, and internal struggles, pushing them to their limits as they race against time to stop the creature before it claims more victims.