Jørgen Kunz

Fourteen-year-old Jan and his companion Erling appear as extras in a film being filmed at Nordisk Film's studios in Valby. A mysterious burglary at the studio's fine mechanics workshop gives the two healthy boys the opportunity to act as detectives.

Per Brask is a fisherman's son, a lively 16-year-old boy, still too young to go out to sea, even though, like other boys on the west coast, he has to help out with the daily work. He is mostly preoccupied with playing, while dreaming of getting his own boat. The boys from the dunes are in a constant battle with the fjord boys, or land crabs – usually just called crabs – who are the boys from the village by the fjord or from the farms further inland.