The film is set during the Russian Civil War in the period of the Red Terror. In a provincial Cheka (the All-Russian Emergency Commission for Combating Counter-Revolution and Sabotage) office in an unnamed small town, a routine bureaucratic work is taking place. Every day, a Cheka troika tribunal made of director Srubov and his assistants Pepel and Katz reads out a long list of all kinds of real and perceived counter-revolutionaries and class enemies. Those arrested are always immediately found guilty and the sentence, regardless of the accusation, gender and age of the person, is the same – to be shot.
The terrible conveyor of death operates in the basement, overseen by Srubov: the prisoners are systematically taken out of their cell, ordered to undress, placed against the wall in fives, and shot, usually in the back of the head. Following the secret killings, the naked corpses are then dragged by feet through a special window in the cellar, loaded into a truck, and taken away, to forever disappear without a trace.
Srubov, a young man from an intelligentsia family, philosophically talks of the historical necessity of extermination in the service of the Bolshevik Revolution. He is highly organised, dutiful, ruthless, and absolutely loyal to the cause. Eventually, however, pangs of conscience become so unbearable to Srubov that, after his own father is shot by his Cheka comrade and personal friend Katz, he experiences a nervous breakdown and is committed to a mental asylum. Medical examination reveals a stigma in the shape of a bullet scar on the back of his head. In a sequence ominously similar to the executions, he is ordered to undress, placed against the wall, and sprayed with water from a hose.