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.

When Joris (Martijn Nellestijn) and Boris (Richard de Ruijter) of a notary is an important but mysterious heirloom in hands, the duo goes in search of the precious possessions of their ancestors. While Inspector Jankers (Frederick the Great) thinks that the duo wants something naughty tricks, he follows them to the island of Cyprus. If George and Boris friends with Max, Michael and Anna end up in the hotel Aunt (Inge Ipenburg) and her sidekick Grudo (Bartho Braat). These two, however suspiciously interested in the quest of the group of friends ...

To celebrate Appie's birthday, the Anubis residents rent an old haunted house. However, strange things start to happen when the friends disappear one at a time.

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.