During the Russian Civil War, orphan Fyodor (Fedka) Trofimov, whose father was killed by Whites, is adopted by a Red cavalry unit.

Not being able to implement his invention in his home country, engineer Arrowsmith, the author of the patent for ore flotation, goes to the USSR to work at one of the flotation plants, where he soon learns that a group of Soviet engineers is conducting similar work.

About how the boys of the Kabardian village help adults to raise fleet-footed horses.

About the childhood years of the hero of the Civil War, Marshal of the Soviet Union Semyon Budyonny.

The secret police agent finds that factory director wife is counterrevolutionary but dies from the heart attack. The director reads the diary of an agent and turns his wife to police.