The film follows the career of detective inspector Marianne Atzeroth-Freier through the Hamburg police force of the 80s and 90s. At the end of the 70s, Marianne is 30 years old and a single parent; she becomes one of Hamburg's first female police officers. Marianne is one of the first women ever to be promoted to the Hamburg homicide squad. The opposing forces in this male-dominated world are strong, she is not really taken seriously and is even bullied along the way, until she comes to the attention of the furrier Lutz R.. Against the considerable resistance of her superior, Marianne investigates in her spare time and makes a significant contribution to solving the case of the "acid barrel murderer".