Schwerin is sweating. It's the hottest summer in years. Detectives Lona Mendt and Frank Elling investigate a man who was hung upside down in his bathroom with his throat cut. When another victim is murdered shortly thereafter, the act of a serial killer becomes apparent.

When Jasper is kidnapped and Elling is attacked by the killer, nerves are on edge and Bernd Peters forces Lona to make a momentous decision.

Frank Elling and Lona Mendt have to cross moral and legal boundaries to get to the motive for the murder series and thus the masterminds behind the conspiracy.