The wealthy factory owner Osten has achieved his position thanks to his energy and diligence. However, he has one weakness - he cannot admit that he too must grow old one day. What scares him most is the thought of becoming a grandfather. To prevent this, he is willing to become a rival in love with his own son. One day, Jiří has ​​had enough of his father's actions and decides to leave his house and his comfortable life. He even changes his name and starts working in a competing factory as an ordinary worker to prove to his father that he too is capable of working his way up from scratch. That is when Jiří meets the energetic seamstress Tonička, who is studying in the evenings to become an office worker. The young people are happy together, but the factory owner Osten comes between them. He offers Tonička a position as a secretary and is ready to win her over...