Criminal investigation officer Ivan Opalin is on his way to replace his comrade, who, together with other agents, is waiting in ambush for members of a bandit gang. Due to an accident on the road, Opalin arrives late and discovers that his comrades have been killed. They begin to suspect him of being involved in what happened, and then he plans to defeat the bandits on his own. However, he cannot do without help, and Opalin finds an extremely unexpected accomplice...