Leopold Kohák married a rich widow a long time ago and now has nothing to do compared to his energetic wife. He's growing old and troubled by the fact that he betrayed his first love Emča and his beloved river Sázava where he spent his childhood and youth. A visit from an old friend Lebeda brings it all back to him. After a nervous breakdown Leopold secretly visits his home instead of going to the spa. A wandering tramp suggest Leopold should bathe in the magical waters of the Sázava, and slowly his youth returns to him.
Karla, a bar dancer, shoots her lover Mayer during a break-up. She hides from the police in pianist Pavel Ryant's apartment and promises to return when she leaves. The next day, however, Karla is arrested and convicted. In the penitentiary she meets the warden, Angelika, a nun who is very much like her. She begs Angelika to lend her clothes for a few days and leaves the prison as a nun.
This light-hearted comedy operetta tells the story of a newly appointed high school professor who becomes an ideal target for pranks and jokes.