The movie describes proletarian life in the Czech Lands after World War I.

Cashier Ferdyš Pištora goes to rob the villa of banker Rosenštok. At that moment, a fire breaks out and Ferdyš saves the banker's two young children. He is hailed as a hero by everyone and Rosenštok makes him a messenger in the bank. This changes Ferdyš's entire life. He becomes a moralist and bullies the whole neighborhood with his sermons. He falls in love with Terezka, a member of the Salvation Army. Ferdyš's former lover Irma is jealous of Terezka. The two women argue and Terezka, in anger, claims that she killed her child and buried it in the cellar. Ferdyš believes this fabrication. In order to save her, he wants to give her the money that he was supposed to hand over to the bank. Out of jealousy, Irma tells the police that Ferdyš wanted to rob the banker's villa, and Ferdyš is arrested. However, Rosenštok intercedes for him and Ferdyš is acquitted. Terezka confesses that she made up the child's murder and celebrates her wedding with Ferdyš.

In the Škoda factory, where they are feverishly rearming in 1914, works the foreman Kalina, the father of the young men Pavel and Jan. Pavel is a supporter of the monarchy, while Jan, on the contrary, defends the idea of ​​our national independence. Just before mobilization, Jan escapes to Russia, where he joins a group of volunteer legionnaires called the "Czech Company", fighting against the Austro-Hungarian monarchy. Pavel enlists in the Austrian army. The brothers do not meet again until July 1917 in the battle of Zborov in Ukraine, which marked a successful breakthrough of the Austro-Hungarian front.