At the beginning of the war, the Germans throw their saboteur into the USSR. The landing is unsuccessful - the spy is captured by the NKVD. When trying to escape, a saboteur who turned out to be a Russian thief in law, accidentally remaining in the occupied territory, dies. In order to find the other spies involved in the operation, the security officers have to turn to the criminal's twin brother, a rural teacher. He takes the place of the deceased in the German intelligence network and enters into a deadly game...

West Belarus, October 1944. The German command is trying to prevent Soviet troops from entering East Prussia. In order to exclude the leakage of information about their plans, the Nazis use a new code, which is to be solved by Soviet radio operators. This is the task that Major-General Zharov and his subordinates receive. To protect the scouts ordered to a group of Captain Belov, which has already once saved the general from the attack of the German landing force.