The film covers the period from 1900 to 1917. Historical events—the Russo-Japanese War, January 9, and others—are shown through the eyes of a mother who begins to realize that her children have many like-minded followers, and thanks to this, she comes to believe in the feasibility of the ideals for which her eldest son sacrificed himself. Only the awareness that his cause is not hopeless, that it is achievable and close to victory, gives her the courage to endure separation from her loved ones and wandering.

Boxer Mikhail Marchenko quarrels with the guys from his brigade. And tomorrow they were going to set another record for coal production. The brigadier decides to replace Marchenko with Nikolai Mironov, who returned from prison and caused an accident at the mine five years ago. However, the brigade is against this decision.

Based on the play by A. N. Ostrovsky.