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.
Stefan Danailov
as Veselin
Vera Dragostinova
as Yuliya
Krasimir Medarev
as Pesho
Georgi Naumov
as Charli
Valentin Vasilev
as Bebo
Miki Cherneva
as Zhivka
Marko Sambiozi
as Italiancheto
Grisha Boyadzhiev
as Doncho
Sasho Aleksandrov
as Chervenokosiya
Lyubomir Kirilov
as Colonel Filipov
Ivan Komitov
as Captain Naumov
Nikolay Uzunov
as Toromanov
