Fourteen-year-old Mara hires Max the detective to track down her missing mother. However, Max's son Sam and his friend Ortwin are very concerned because Max doesn't realize that Mara is a witch. Sam and Ortwin do everything they can to expose Mara.

This is the third movie from the "Mijn Vader is een Detective" film series.

Sam and Star had long been friends. Sam's father is a detective and thus learn to know Ortwin. Ortwin's the rare parrot is in fact stolen. Ortwin's father enlists the help of Max, but Max is kidnapped during their quest by a gang of criminals. The kids put a chase with a speedboat and end up on a mysterious island fortress.