The Rostock crime team is dealing with a dramatic crime in: two people die on the street. A young man stabs a woman to death and then executes himself. At the crime scene, Katrin König and Melly Böwe are faced with a mystery, because there is no recognizable connection between Leon Schilling (Karl Seibt) and the manager Mona Färber (Nora Moltzen). The only clue is a message on Schilling’s cell phone – “Do it!” – on the night of the crime. The message comes from Felix Lange (Sebastian Jakob Doppelbauer), a 28-year-old teacher, but he denies any involvement in the crime. But this is not the first time he has testified in a similar context: Felix was also in contact with Lara Trensbach (Samara Fry), a 19-year-old woman who also committed suicide recently in Rostock.

Investigators König and Böwe suspect that Lange, under the pseudonym “Wintersonne”, was targeting emotionally and psychologically vulnerable people in internet forums in order to persuade them to commit suicide. Were Lara and Leon just the first in a series of planned victims? Is the ostensibly ambitious teacher planning to trigger a wave of suicides?

Die Ermittlerinnen König und Böwe vermuten, dass Lange unter dem Pseudonym “Wintersonne” in Internetforen gezielt emotional und psychisch verwundbare Personen anspricht, um sie zum Suizid zu bewegen. Waren Lara und Leon nur die ersten in einer Reihe geplanter Opfer? Plant der vordergründig ambitionierte Lehrer, eine Welle von Selbstmorden auszulösen?