In "Helen Dorn - Schwarzes Herz", Helen (Anna Loos), who is struggling to settle into her new flat share with her father (Ernst Stötzner) and Weyer (Tristan Seith) in the farmhouse she inherited, has to investigate a new case within her own ranks. Police officer Ralf Lenze (Henning Flüsloh) has stopped a civilian car on a country road just outside Hamburg at night and then opened fire on the driver for no apparent reason. The victim's wife (Karoline Eichhorn) and daughter (Lara Feith) were also in the car. Jens Falkner (Stephan Schaad), a successful and respected business lawyer, struggles with death in hospital after the attack.