Policeman Haller becomes a fire policeman in Munich, in order to find back his fiancée Hilde. After a while, he really finds her, but she is still jealous because of a dancer Haller flirted with. Also, Haller suspects Wiedemann to be a competitor in his fight for Hilde's heart. Suddenly, Haller finds out that Wiedemann is a criminal and plans to rob the safe of the chemistry lab Hilde is working in. Haller wants to bust Wiedemann alone, but some things happen that make it all much more complicated.