The story of Little Peter and his sister Anneli, who help a May beetle named Mr. Zoomzeman (German: Herr Summsemann) to retrieve his missing sixth leg from the Moon. After a fantastic and dangerous overnight adventure they recover the leg and are returned to their beds at home.

Dutch police officer Van der Valk is pulled away for a private investigation for a friend of the chief of police to find the missing junior manager. When he gets to know his woman, he is fascinated by the thought of running away with her.