In the Dortmund crime scene "Masks", young police chief Nicolas Schlüter is hit by an approaching car with full intent. Schlüter was about to be promoted, he was popular at the police station and had good friends, his wife Simone is expecting their first child. There does not seem to be any evidence of a murderous motive or a suspect. The team of Peter Faber (Jörg Hartmann), Martina Bönisch (Anna Schudt), Jan Pawlak (Rick Okon) and Rosa Herzog (Stefanie Reinsperger) investigate in all directions - including at the police station in Dortmund-Hörde. There Martina Bönisch meets an old friend: At the police school, she got along very well with Katrin Steinmann (Anne Ratte-Polle). Today the head of the guard stands protectively in front of her team. In the weeks before his death, Nicolas Schlueter had apparently targeted a doctor in particular: Dr. Johannes Oberländer (Simon Böer), who has made a name for himself as a seminar leader. Men should be able to learn from him how to be well received by as many women as possible.