It all begins at Prague Airport, where American agents have brought Major Maisner, who has been expelled from the United States, in handcuffs. He returns to his place of work, the Central Police Academy, despite having been demoted to lieutenant for his "performance" and his position as academy commander having been taken over by the newly promoted Captain Hrubec. Maisner meets his former students, who now teach at the school. They all welcome him enthusiastically and receive gifts from him. While psychologist Kudláková, who is attracted to commanding types, has lost interest in the demoted Maisner and is now passionately in love with Hrubec, Boženka Vinklářová, who has broken up with the gypsy Štefan and now teaches dactyloscopy at the school, focuses her attention on him. Maisner recounts how he jumped off a skyscraper in America to defend himself against Simona Ptáčková's advances.