Detectives Lona Mendt and Frank Elling investigate the case of a man who was hung upside down in his bathroom with his throat cut. When another victim is murdered shortly afterwards, the crime of a serial killer becomes apparent.

A lead takes the investigators to a campsite in Marnow as they being to sweat under the pressure.

The two detectives Frank Elling and Lona Mendt have to cross moral and legal boundaries to get closer to the motive of the murder series and thus to the people behind the conspiracy. Lona suffers a heavy blow of fate.

Frank Elling and Lona Mendt must enter the lion's den. All the clues point in one direction and to powerful backers. When they finally get an important witness to testify, she is murdered.

Lona shoots the corrupt LKA colleague Bernd Peters, leaving him seriously injured. The detectives blackmail him so that he will not betray them. Meanwhile, Jasper manages to escape from his kidnapper, but has a fatal accident on the run.

The commissioners can finally reveal the motive of the serial killer. Apparently he kills people who are involved in a medical scandal. These people are also the people behind sabotaging the investigation.