A mysterious prisoner falls into the hands of the Germans. What could be interesting about a person who has lost his memory and does not remember anything about himself? But it is he who suddenly becomes the reason, because of which the long-term stubborn struggle of Soviet and German intelligence is suddenly sharply aggravated. The most serious forces are involved on both sides, the most experienced specialists and masters of their craft are involved in the operations. A new special unit of the NKVD - Department "B" is connected to the case. Now his employees have to prove their skills in practice. Even their instructors - and they go into battle, on a par with their yesterday's students. After all, they have no right to lose.