Babs Sprenger (Anna Tenta), a successful businesswoman who lives alone in a spacious apartment in Fürth, was active on various dating portals under an alias until a few months ago. She celebrates her birthday alone with her colleague Theresa Hein (Anja Schneider). The next day, Babs Sprenger is dead. He was stabbed with a sushi knife that the police found clean and in the dishwasher. The knife was Theresa's gift to Babs. Why did it become a deadly weapon? What happened that evening? Even after Theresa's confession, the question of why remains open. Voss (Fabian Hinrichs) and Ringelhahn (Dagmar Manzel) suspect that the truth lies much deeper. What is Theresa hiding?