1944, Moscow. In 1941, the capital's most important facilities were mined in case of a possible capture, but due to a lack of plans and the deaths of many personnel, some of these explosive devices remained unaccounted for. Upon learning of this, German intelligence sends agents into the Soviet rear to carry out a series of explosions in the center of Moscow and create chaos, including involving prisoners of war. Lavrov and Semyonov, members of SMERSH, must identify the saboteurs and prevent a catastrophe in a situation where any mistake could lead to widespread destruction.