The nine-year-old Prague boy Pepiček flies to Moscow as an involuntary stowaway on an airplane. Together with the Soviet pioneer Mischa, he pursues an alleged agent in the hustle and bustle of the World Festival and is flown back to Prague in the evening.
| Actor | Role |
|---|---|
 Mark BernesPilot | Pilot |
 Nikolay KryuchkovCab Driver | Cab Driver |
| TTomáš SedláčekPepicek | Pepicek |
| VVladimir SiluyanovMizha | Mizha |
 Liliya Yudinastewardess | stewardess |
 Elza Lezhdeystewardess | stewardess |
 Yuriy Sarantsevflight engineer | flight engineer |
 Vasili Neshchiplenkosecond pilot | second pilot |
 Jana DítětováNot listed | Not listed |
 Miroslav HomolaMagician | Magician |
 Stanislav FišerNot listed | Not listed |
 Izolda IzvitskayaNot listed | Not listed |
 Viktor Uralskycontroller at VDNKh | controller at VDNKh |
| LLev LobovNot listed | Not listed |
| VVladimir Razumovskiy(uncredited) | (uncredited) |
| LLena Ilyinskayaepisode | episode |