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.

The film features the six children of the Telerin family, characters created by the brothers José Luis Moro and Santiago Moro. The Wizard gives each child a dream; the six dreams are presented in different graphical styles.