The story revolves around a charming girl named Katerina. She lives in the countryside and works as a teacher at a local school. The children love her for her gentle and cheerful nature, while her colleagues respect and appreciate her professional qualities. Katerina is soon to marry a local deputy named Andrei. She wants to invite her sister to the wedding, with whom she hasn't been in touch for many years. Soon she learns that her biological sister has long passed away, but she left behind a son...