The plot revolves around Captain Pavel Koltsov, an agent working for the Soviet secret police who is spying on the White Volunteer Army, posing as an adjutant to a chief commander, general Kovalevsky.

In the spring of 1919, Pavel Andreevitch Koltsov (Yuri Solomin), an agent of the Reds, is sent as the head of the Cheka by Martin Latsis into the Volunteer Army.

Koltsov runs several covert operations while successfully passing all tests regarding his legendary status and does not give in to provocations of the counterintelligence.

At the same time there is a romantic side plot in which Pavel Koltsov wins over the daughter of Colonel Shchukin Thani, chief of counterintelligence.

At the end of the film Koltsov sacrifices himself to destroy the special train of the Whites with British tanks, which is driven to the front.