Summer of 1943. In the Kursk Salient area, by order of the Stavka, a strategically important stretch of railway is being built. To destroy the target, the Germans send a group of saboteurs into our rear. One of them, a German woman named Elsa, managed—by the fighters of SMERSH of Lieutenant Sergey Sobol—to be taken alive. But the interrogations yield nothing. To identify the agents and traitors involved in blowing up the railway, the operatives come up with a clever plan. Sobol arranges an escape for Elsa. That creates a chance that she will lead the SMERSH men to her accomplices. What happened afterward became a terrible surprise for everyone involved in the operation…