Arthur and the Minimoys.

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.