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.

Inspector Cadek from the 13th police station should keep an eye on the released safe-cracker nicknamed The Cat. He rightly suspects that Cat will go and pick up his last loot which the police didn't manage to find and that he will want revenge on Karta who helped get him behind bars. At the hospital, Cat's ex-lover Fróny hopelessly falls for doctor Chrudimský and decides to start a new life. She still refuses to help the inspector in his search for The Cat and Karta.