The events of the film take place during the First World War in 1917 on the Caucasian front. First cornet of the military orchestra Streshnev, not interested in politics faithfully serves his stern commander Colonel Garaburde. The musician learns that on the orders of Colonel a firing squad is prepared for a unit on which his son Streshnev Jr serves. The awakening of class consciousness of the old tsarist army campaigner forces him to join the rebel soldiers and warn his son and comrades of the impending danger.