The beautiful "Blue Bird" schooner is sailing along the Adriatic sea coast. The passengers of the schooner are children of different nationalities, winners of the competition "For Peace and Mutual Understanding". During this wonderful sea voyage children find out that there are smugglers on board the ship...

Young farmer Mikajlo while on youth labour action falls in love with a student Nada and infatuated with her, he leaves the peasant brigade and Malena, a girl who as if she were overabundant, followed him to work the labour action. Mikajlo's courtship of Nada provokes laughter and ridicule, so ambitious 'Don Juan' returns to his brigade and the girl.

Young farmer Mikajlo while on youth labour action falls in love with a student Nada and infatuated with her, he leaves the peasant brigade and Malena, a girl who as if she were overabundant, followed him to work the labour action. Mikajlo's courtship of Nada provokes laughter and ridicule, so ambitious 'Don Juan' returns to his brigade and the girl.