Ani, a charming young girl, is a driver at Sofia Airport. She sends a letter to her boyfriend Boyan, a worker at a large construction site. The letter contains a single word "yes". Boyan starts preparing for a wedding. The Soviet pilot Andrey will soon return home after several years spent working with his Bulgarian colleagues. They arrange a farewell tour of Bulgaria for him on which Ani has to drive him. Because of mistaken jealousy, Boyan tears up his sweetheart's letter.
This is a typical story from the 'cold war' era. A group of kids play on a quiet street in Sofia. From a nearby window falls a key. The helpful youngsters quickly return it to the owner, but in the haste switch the keys. The unintentional error disentangles a whole spy story. The young detectives doubt the good intentions of the man they tried to help. It turns out that the key is from a secret apartment where saboteurs are hiding. The secret network is exposed to the authorities and the kids feel like heroes.
The successful factory owner Sasho Kamenov marries Maria. Sasho wants to surprise Maria with a villa on the seaside. He commissions the project to architect Karshev who begins to court Maria. Kamenov sends his wife to the seaside. There Maria meets Karshev. She feels unwell in the car and the medical examination reveals that she is expecting a baby. In her joy at the news she accepts the architect's invitation to go boating. A raging storm keeps Maria at Karshev's villa. Kamenov accuses his wife of adultery and chases her away. After a while he repents and goes abroad in search of his wife... Sasho discovers his wife singing in a club in Nice. She tells him everything, he asks her to forgive him and soon the happy family makes a photograph.
