A small Moravian town near Brno in the 1920s. In a forest clearing, the mentally disabled Fricek discovers three dead young people: the nineteen-year-old daughter of the local forest ranger Růžena, the butcher's assistant Hrnčíř, and the former student Roubal. Thus begins a detective story that screenwriter Roman Ráž wrote based on a true story. Inspector Vrba is in charge of investigating the case.