Far East. 1922. A member of the party's underground regional committee, Pyotr Kokorin, arrives at the partisan Tumanov detachment of Vladivostok and defines the task of the detachment: to seize wagons with weapons from the White Guards, unite with other detachments and retake Zhukovka, supporting thus the offensive of the Red Army.
In the squadron, he meets his brother in love with the squad nurse. But the girl gives her heart to the elder. In the meantime, all movements of the detachment become known to the White Guards - an enemy agent turned out to be among the partisans ...