A comedy about well-hidden children, a diabolical plan, and how it all came to light in the end. There are situations in life when everything gets tangled up somehow. People, especially when they are still young and inexperienced, sometimes break up and get together too quickly, and the consequences may only become apparent many years later. In this particular case, they came to light when Gábina and Petr decided to get married. Everything would have been fine if Petr's father and Gábina's mother hadn't realized during their introduction that they had actually known each other for a long time and, worse still, that their children were siblings who had been well hidden until then. The mistake had been made, and now what? How to separate the young couple without arousing their suspicions, and especially those of the rest of the family? Yes, a diabolical plan must be devised...

High school teacher Jiří is torn from his solitude and everyday life by an unexpected nighttime visit from his beloved younger sister, former seamstress Růžena. She tells her brother that she has run away from her husband Fanda, a textile merchant, because of his greed and vulgarity. However, Jiří later learns from his other sister, Tylda, that Růžena spent a lot of money and left her husband for a dragoon captain. The captain has now rejected his pregnant lover because he is getting married. Disappointed, Růžena believes that her brother has turned away from her because of her lie, and she decides to take a desperate step...