Ten-year-old Arthur, in a bid to save his grandfather's house from being demolished, goes looking for some much-fabled hidden treasure in the land of the Minimoys, tiny people living in harmony with nature.

Arthur answers a distress call from Princess Selenia, who is menaced by the nefarious Maltazard.

With Maltazard now seven feet tall and Arthur still two inches small, our hero must find a way to grow back to his normal size and stop the Evil M once and for all, with the help of Selenia and Betameche.