Arthur is beside himself: today is the end of the tenth lunar cycle and he can at last return to the world of the Minimoys to get back together with Princess Selenia. In the village, everything is ready to welcome him: a great banquet has been organized in his honor and the little princess has put on her dress of rose petals.

It is precisely this long-awaited day that Arthur's father chooses to leave his grandmother's house earlier than planned. Just when they're about to leave, a spider drops a grain of rice into the young boy's hands, on which a message of distress is engraved.

There is no doubt: Selenia is in danger and Arthur now has only one thing in mind: to fly to her rescue! He'll do it, even if it means using a makeshift passage, falling headfirst into Max's bar, coming up against troops led by Krob, the new tyrant of the Seven Kingdoms, save Betameche, fight rats, frogs and hairy spiders, and discover, once he arrives at the Minimoys' village, that no request for help had ever been sent to him!

Who was it then who's tricked our young hero?