Colonel Velyaminov begins to suspect that Yampolsky is not who he claims to be and that he might be the saboteur; Urusov sends his scouts to the commander of the partisans in an effort to shed light on Kardash's past.

A big division of the Soviet troops gets into the encirclement of the Germans; the only connection with big land is a narrow isthmus; Germans prepare a breakthrough; there is a dangerous saboteur among the Russians.

Colonel Velyaminov begins to suspect that Yampolsky is not who he claims to be; Yampolsky-Urusov sends his scouts to the forest, to the commander of partisans who is the only person who can shed light on the past of the local special officer Kardash.

Scouts are sent to another partisan detachment where they see that the camp is empty, all are killed; in the distance, there is a knock of axes: saboteurs pretending to be partisans are chopping wood to put log on the road for German tanks.