"Where are you, coward?" Angelika Flierl asks herself. She just witnessed an unknown man randomly harassing a woman in a park, and then hitting her fiancé so brutally when he tries to intervene that he dies shortly after. It's the hardest kind of homicide to solve: a totally random act without a real motive. The front page headlines have the police on the spot. Unpleasant department chief Zangel and district attorney Holzmann put pressure on the investigators, Angelika Flierl, Harald Neuhauser and Ludwig Schaller. Especially Schaller goes out on a limb when he uses his inductive mode of investigation, hoping for the right inspiration. Either he succeeds - or he'll be suspended.