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.

• Boyana Film
• Stefan Danailov
• Vera Dragostinova
• Krasimir Medarev
• Georgi Naumov
• Valentin Vasilev
• Miki Cherneva
• Marko Sambiozi
• Grisha Boyadzhiev