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.

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.