It is 1941 and the German occupying forces are taking over Yugoslavia, making a train ride to Kraljevo a dangerous game for a secret communist agent carrying important documents. Both the Germans and the police are looking for him on the train, and his safe arrival in Kraljevo seems like an impossibility. His determination to get the papers to the right people keeps him going, even through a gun battle after the train arrives - challenging him to find a way to complete his mission.