In the forest near the village of Drahovice, a nurse from the local health center is found murdered. Three months ago, another young woman died nearby and a sexual motive was proved in the case of her murder. In the case of the nurse, the motives are not so clear. Two criminologists from Prague - Major Kalas (Rudolf Hrusínský) and Lieutenant Varga (Radoslav Brzobohatý) - patiently collect all available leads and question the villagers.