The Great Patriotic War. Soviet intelligence officers led by Sergei Skorin and Andrei Losev are trying to track down a well-trained sabotage group that is staging large-scale sabotage in the rear of the Red Army on the eve of the Battle of Kursk. Andrey and Sergey are brothers, but there has been a conflict between them for many years. Andrey does not trust Sergei, because he suspects that his brother has been turned upside down.

1944. After the hospital or because of problems with vision and speech, several officers are "written off" to a false airfield. The Nazis take this airfield for the real one, and pilot Ivan Polivanov learns about it at the most inopportune moment.