Chief engineer of Saarländ's Rosdorf nuclear plant Georg Bekker appears dead, supposedly of a drug overdose, and detective Max Palu takes charge of the investigation, meanwhile, Georg's sister starts recieveing mysterious floppy disks and becomes the target of threats along her daughter.

The body of a retired woman is found in a Berlin rental apartment—she died in agony after a fall that had occurred days earlier. Inspector Franz Markowitz discovers evidence of an intruder at the crime scene and refuses to accept the simple theory that it was a botched burglary.

A psychopathic former actor escapes from a psychiatric clinic to take revenge on the woman who put him behind bars: Detective Lena Odenthal. While Hans-Martin Carsdorff perfidiously stalks and psychologically terrorizes the detective, Odenthal must simultaneously solve the murder of an elderly woman.

The son of an old crook is murdered. This crime brings the Düsseldorf homicide squad, as well as Hans Gebhard (the father) and Kalle Maisch (his old criminal buddy), into action.