In the winter of 1889, in St. Petersburg, a murder occurs: Generalship Shturndman and her maid are killed. Suspicion falls on the lackey, but investigator Mechislav Kunzevich—thanks to a hat-box found in the apartment—tracks down the suspected murderers. The accomplice could very well be the girl whom Kunzevich is in love with. The behavior of this pretty shop girl raises a lot of suspicions. And when, during the investigation, the detective learns that the criminals who killed the generalship also committed another murder—an actress from Marseille—he has to take a serious look at the girl who stole his head.