On the fight against sabotage at a Soviet enterprise in the first years of industrialization. 1921 A detachment of red horsemen under the command of Commissar Bobrik pursues the remnants of the White Guard gang. The band is scattered. But her ataman almost managed to shoot Bobrik, who was stuck with his horse in a swamp. Buntsevich, a blacksmith from a neighboring village, helps Bobrik get out of the swamp. It takes 8-10 years. A power plant is growing among swamps and dense forests. Commissar Bobrik is the head of the party organization of the power plant. The former blacksmith Buntsevich works here as a fitter. A new worker appears at the station - a certain Trofim Ivanovich ...