A car deliberately runs down a young man on a road by a small border town. The locals recognize the dead man as one of the students who were there on volunteer work some time before. The police detectives, Major Kalas (Rudolf Hrusínský) and Lieutenant Varga (Radoslav Brzobohatý) can then get on the trail of the people with whom the victim was involved, especially at the photographic studio headed by Bohuslav Pacer (Bohus Záhorský).