The murder of the successful lawyer Mohr leads Ritter and Stark into the world of big city singles. Mohr was a regular guest at various speed dating establishments, although he had an affair with his attractive colleague Nina (Aglaia Szyskowitz). Was jealousy involved? Because there is also Kirsten (Elena Uhlig), whom Mohr met during speed dating and with whom he began a relationship. Both women have a motive; and Kirsten, the impulsive saleswoman in a boutique, had also learned through an indiscretion that Mohr's law firm was not averse to tax fraud. Kirsten runs away when she realizes that the police are on her trail. But her older brother Paul (Timo Dierkes), who has an extremely close relationship with his sister, also comes under suspicion of murder.