While out looking for a Christmas tree one winter day, siblings François (François Gosselin) and Katou (Catherine Leduc) encounter a bizarrely dressed entity (Dirty Money’s Marcel Sabourin) who emanates bubbles and shoplifts from a convenience store. With Katou convinced this “man” is really a Martian, the children follow his green trail all the way to a flying saucer. After confirming his alien identity, they form an instant bond and pool their efforts to fix the Martian’s damaged spaceship, so he can return to his home planet. Meanwhile, the police join forces with a vigilante mob to track down this mysterious visitor and put his antics to an end.