A butter boat on the Danube: the entertainer Rolf Gembel (Max Tidof) straightens his hairdo, puts the obligatory flower in his buttonhole and hopefully heads towards the stage in order to sell as many blankets as possible today. And then the unbelievable: like a still life, peacefully wedged together, ten people in the auditorium. Unconscious? Dead? A sign of life can only be found in Greta Wache (Renate Becker). The elderly lady, unable to be questioned, was brought to the clinic by Dr. Sion (Hannes Jaenicke) admitted. Inspector Ellen Lucas must assume a murderous robbery as all valuables, jewelry and credit cards have been stolen.
Toni Kehring, who was helping part of the group as a nurse and was observed fleeing the ship, is suspected of having committed a crime. Mysterious, tooStatements by his wife Anne (Jenny Schily), who runs a mobile nursing service and had contact with some of the victims. And Gembel also seems to know more than he cares to admit. Suddenly there is a new clue to the case: Ellen's landlord Max (Tilo Prückner), who is in the clinic of Dr. Sion to observe his heart, tells of an intimate encounter between Anne Kehring and Dr. sion When detective Lucas finds out that some of the victims at Dr. Sion was being treated and she gets in touch with his father (Hans-Peter Hallwachs), who vigorously propagates the right to a self-determined death, things start to move in the case.
The situation escalated when shortly afterwards the body of the nurse Toni Kehring was fished out of the depths of the Danube. When Greta Wache breaks her silence, light comes into the darkness of the case...