The film is based on a classic 1903 Dutch children's book of the same name, written by journalist Marie Joseph Brusse.

Jan, nicknamed “rascal,” (Boefje), forever gets in trouble with his harried mother, who maintains their squalid apartment and cares for his three sisters, while his father works long days and routinely beats Jan. Jan and Pietje roam the city, committing petty thefts, and dreaming of being wealthy gangsters in America, based on adventure stories they read.

The housekeeper argues that people cannot change their inherent nature, while the Pastor believes they can, if they are in a loving, supportive environment.

A short time later, Jan gets into an argument with Pietje’s mother and spitefully throws hot coals into her apartment, nearly burning it down.

Jan dreads the place, his head filled with nightmarish images, but once he arrives, the priests are kind and patient and his fellow students are decent to him.

Flush with cash, Jan buys gifts for his family and returns to them with lies about how he was given the money by the reform school and sent into the city.

Jan asks the Pastor to protect the rats, then finds himself drawn by the beautiful music of the pipe organ back to the priest he met before.

Sierck left before editing was completed, without seeing the finished film, and went to work in Hollywood under the anglicized name of Douglas Sirk.

Detlef Sierck told executives at the UFA Studios that he was traveling for location scouting for Wilton's Zoo as a cover story for his escape from Germany in 1937.