There is a state of emergency shortly before the Kiel Week. Three million guests from all over the world are expected to celebrate the largest summer festival in Northern Europe. Now, of all times, a treacherously murdered woman is found in an empty apartment in the middle of the city center. There is no trace of the perpetrator, who had evidently set himself up in hiding for months. When inspector Borowski looks around the victim's apartment, he suddenly finds himself in front of a wall of fire. Roman Eggers and the inspector face each other for a moment. Eggers tries desperately to annihilate the consequences of his crime - and saves Borowski at the last moment. Then he disappears into the anonymity of the city, which is slowly filling up with people. When another body is found, Borowski and Brandt are alarmed: Are they dealing with a serial killer?

Borowski's last case led to the transfer of his colleague Sarah Brandt. In order to escape the anger in the commissariat, Borowski plunges into a case that leads him into the vast landscape of the North Frisian Wadden Sea. On Suunholt, a small, sleepy North Sea island near Denmark, a man was found dead who is no stranger in Kiel. Years ago Oliver Teuber was the key figure in a corruption scandal. The dead man had apparently found a new life and a new love far from Kiel. On Suunholt, the commissioner faces the completely disbanded Famke Oejen, who found her lover lifeless in her shared bathroom. Borowski is captivated by the mysterious atmosphere of the strange islanders.

In the middle of an event at the police college, a young student freaks out and stabs her buddy. He still dies at the scene in the arms of the helpless main commissioner.

Alarm in Kiel: In an uprising in the forensic clinic, the woman killer Kai Korthals manages to escape from security custody. Korthals, who crept and killed numerous women in their homes, became Borowski's personal nightmare six years ago when he kidnapped his fiancée Frieda Jung.

A killed infant is found in a parking lot near Kiels. Where's the mother? Did she kill her child? A found entrance volume leads Klaus Borowski and Mila Sahin to the sleepy town of Wacken in Schleswig-Holstein, which wakes up once a year when the world's largest heavy metal festival attracts 80,000 fans. The first trace leads the commissioners to Caterer Michi, who apparently took the young mother with him.

In a rental property in Kiel, Klaus Borowski and his colleague Mila Sahin find 40-year-old insurance clerk Andrea Gonzor shot dead on her bed. Andrea Gonzor had apparently invited people to an erotic party that evening. Numerous traces of semen around the dead woman indicate that the victim had apparently had several sexual partners that night. There are traces of alcohol and tranquilizers in her blood, but there is no evidence of a sexual crime. Borowski and Sahin delve into the world of sex and love addicts. The only key to solving the problem seems to be Andrea's friend Nele. She discovered the dead woman.

With only days left until his retirement, Borowski uncovers a chilling case linked to a dark house. As he investigates, he's stalked by a killer who anticipates his every move, all while racing against time before his career ends.