The engine-driver Matys rescues his locomotive, which he affectionately calls Lisa, from the Second World War dive-bombers. He himself, however, is wounded during the attacks. Recovering at home, he looks forward to the end of the war so as to be able to ride his repaired locomotive again. The war finally comes to an end. Matys's son-in-law Vojta is an engine-driver, too. On the day his son is born, Vojta gets drunk and forgets about his duty. He is called for, but cannot be found. The colleagues persuade old Matys to secretly substitute for Vojta.