The civil war in Russia, guerrillas fighting with Kolchak formations. As a result of sabotage, accident with white Russian train takes place. In disaster area the flag with the inscription "Wagtail's Army" is found. Kolchak commanders think that they are Bolsheviks, but guerrilla leader does not know anything. It turns out that this is work of three boys.

A kids from "Armiya Tryasoguzki" are fighting "whites" again.