A crime story about a victim who was not entirely innocent. A fashion show is held on board a Danube steamer, where the star is the model Anna Vlčková, nicknamed "the beautiful harlot" because of her acquaintances with wealthy foreigners. Coincidentally, the young police captain Strelková and her older colleague Lieutenant Michalek are also among the spectators. Neither of them has any idea that Vlčková has a crush on the sick Swiss industrialist Langer. However, someone threatens her with death because of her intended marriage to him. Langer dies in the hospital before he can marry the beautiful harlot. However, someone still murders Vlčková with a shot from a hunting rifle. For Captain Strelková, this is the first major case of her career, and it is all the more difficult because the investigator has to make her mark in a world that has been the domain of men until now...
