In the summer of 1944, the Soviet command began preparing an operation to liberate Belarus. During an inspection of the front-line strip, the commander of the mechanized corps, Major General Serov, falls into an ambush. Only the counterintelligence officers of Major SМЕРШ Pavel Koltsov managed to prevent the general’s death. During the investigation into the circumstances of the attack, it became clear that the saboteurs acted in two groups. One was destroyed in battle, but where the second went is unknown. Koltsov tries to organize a pursuit—but instead, he unexpectedly discovers an even more serious danger…