Prague in the 1930s. A young, pretty girl gets on a crowded tram. She immediately catches the attention of a young man who not only appreciates the girl's charm, but also tries to steal her handbag discreetly. And so we meet one of the main characters of the film, a swindler, pickpocket and generally strange being Josef Kořínek alias Pépi. In addition to him, the story is populated by other characters from the Prague outskirts. Of course, the film also features the shrewd councilman Vacátko and his inseparable investigators Brůžek and Bouše. They have a sad duty - to track down the murderer of the collector Krále, who was found dead and who lost a sum of money on the way from the bank that could interest many people from his surroundings...