Fleeing from some other children who want to beat him, Olivier meets the ghost of a Pirate who every hundred years tries to find a parchment. Olivier agrees to help him. But in doing so he is captured by a bunch of pirates. The other children of the village discover a door thru time and space in an old haunted house and decide to rescue Olivier from Captain Monbars' pirates.
Dressed as a clown, the clever rascal Grimm holds up the most secure bank of Montreal and takes 30 hostages. While confusing and ridiculing the police with his strange behavior, he calmly manages to rid the bank of a fortune. But then an unsatisfied companion arouses trouble...