In Mannheim's Luisenpark, during a fitness exhibition, the caretaker of the festival hall is murdered. Reiner Palzki, who happens to be on-site with his boss, takes over the investigation. While he is still arguing with his Mannheim colleagues about jurisdiction, one of the suspects dies. Initial clues about the murderer lead him to a secret room in the telecommunications tower. His personal life isn't going any better: his wife is forcing him to join a sports club.