When 42-year-old Sina Priemke is beaten to death in a forest, the trail quickly leads to the university where she taught as a lecturer in computer science. Shortly before her death, Sina listened to secretly recorded, obscene audio recordings between her superior, Professor Brenneisen, and a certain Melanie. This is why the professor is immediately targeted by investigators. As it turns out, all the students and Professor Brenneisen received these audio recordings at the same time. From whom? And who is the unknown Melanie? Neither Brenneisen, nor any of the students, nor Sina's brother André know her.

A burning boat drifts on the Spree in the middle of the night. The police find a burned body that is difficult to identify.

Early in the morning, a man is run over by a car. The emergency doctor called by a passerby can only confirm death - hit and run or murder? When Robert and Mavi arrive at the scene, it quickly becomes clear that it was not an accident. They are able to identify the dead man as Thomas Bülow, who apparently led a solid, middle-class life in Köpenick. Bülow and his wife Anita are expecting a child. Together with his sister, he worked as an heir investigator. Whenever someone dies without a will and no relatives can be found, they come into play. Did someone want to prevent Bülow from finding a distant relative? When Robert and Mavi come across bartender Eckhard Jablonski, who believes that Bülow cheated him out of his inheritance, Jablonski becomes the focus of the investigation.