A group of Young Pioneers goes on vacation to Artek. Among them is Petya Karavayev, who became famous for preventing a train crash. At the train station, a street kid named Kolka starts a fight with him. After taking his documents, Kolka leaves Petya at the station and goes to Artek in his place. The Young Pioneers and their leader immediately see through the deception, but pretend they suspect nothing. Kolka is rehabilitated, and when Petya arrives, he honestly admits to the deception.
The film has been preserved without parts 7 and 8.