On the eve of departure to the Siberian shock construction site, the famous builder and installer Stepan Bobkov throws his wife. However, on the train he meets Annushka, a young concrete worker who also travels to Siberia on a Komsomol ticket. Sympathy arises between the heroes, which is also reinforced by the coincidence of the so-called “production interests”.

Sergey's girlfriend desperately wants him to quit dangerous police job. But Sergey doesn't want to abandon his new case which proves to be quite difficult.