Arthur is a bright, clever and lively 10 year-old who spends his vacations at his favorite grandmother's house. And talk about vacations. Inside her garden there is a world invisible to the human eye. The world of - the MINIMOYS. One day, Arthur discovers a secret passageway that enables him to enter their world and become a MINIMOY himself. In fact, he becomes THE MINIMOY SAVIOR, helping these minuscule little people fend off all sorts of danger, including invasions by the armies of Maltazard, the MINIMOYS' sworn enemy, a despot who rules over the SEIDES. A dreamer and a bit of a loner, Arthur suddenly becomes a fearless hero, and along with his friends Selenia and Betameche, he is going to lead the little people to freedom. But with a trio like this, the road to victory is going to be full of surprises.
Tarash has a brilliant idea: starve Arak the spider by stopping any insect from getting caught in his web. The plan works even better than Tarash thought.
Betameche finds an old parchment that gives its owner the power of invincibility. Free from his fears, Betameche becomes so brave that he turns into Betameche the Barbarian.
Arthur finds his grandmother's engagement ring in the grass of the garden. The old lady must have lost it. The lost ring makes Grandma very sad. How will Arthur help her?
Darkos and the Seides steal all the dragonfly eggs. They use them to bombard the stump through Arak's web. Nearly all the Minimoys find themselves glued to the ground.
Maltazard and Darkos find some flowers. The pollen makes you completely crazy! Tarash comes up with the idea of contaminating the stump with it to invade the Minimoy village.