Lugubrious howls echo in the icy air of Restigouche, where the Three Musketeers are on spring break... It's the traditional March school holiday, and the Three Musketeers take the opportunity to go skiing at Sugarloaf Mountain from Campbellton. But as soon as they arrive, the young detectives witness unusual events. Those strange claw marks deeply engraved on Mr. Zuccanni's luxurious car, for example... And those people talking in low voices about an unknown beast lurking in the mountains.