At the end of the war, the old train driver Matys saves his beloved locomotive Líza from depth charges. However, the locomotive is damaged and he is injured. At a critical moment, he stands in for his son-in-law, also a train driver, and thus prevents a train accident. Despite this, he is sent into retirement. To show what the "iron old man" can do, he reconstructs Líza with a group of apprentices...
Film shows the struggle of the Czechoslovak armed forces against groups of Ukrainian Insurgent Army (UPA) under command Burlak, who tried to pass through the territory of Slovakia.
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.
