The film is about the Ukrainian paramilitary organization of the early 20th century – "Free Cossacks." 

The Free Cossacks were Ukrainian voluntary armed formations that emerged during the disintegration of the imperial army in the spring of 1917, with the aim of creating and defending a Ukrainian state amid the growing revolution, when the issue of public order became acute in the towns and villages of Ukraine. The formation of the Free Cossacks began in April 1917 in the Zvenyhorodka district of Kyiv region.