Marie Wagner is found strangled in a studio above a department store in downtown Munich. Her body lies in a paddling pool, in a broth of indefinable secretions. Under the stage name Luna Pink, Marie shot porn part-time, including the evening before her death. The confiscated footage from porn producer Olli Hauer quickly became the focus of the investigation: a comparison of the registration forms with the number of amateur actors in the film revealed that there was one more actor on the set. Kalli and Semmler set about the tedious process of identifying the actors who were masked during filming to find out who the one who wasn't registered is. Meanwhile, Batic and Leitmayr question Stella Harms, a friend of Marie's, to learn more about the victim.
They find out that Marie worked in a nursing home. Through Stella, the investigators also learn about a conflict Marie had with Sam Johnson, another Munich porn producer. His father was very successful in this profession in the golden days of Munich porn film production, the 1970s. Today Sam Johnson is broke, like Olli Hauer, with whom he is in a permanent clinch professionally. Johnson had lost a lot of money to Luna, who stopped shooting mid-production. Things come to a head when it turns out that chief prosecutor Kysela is Marie's father.