Max is glad to have a little vacation from monster hunting, and is glad to go away from Boston to the White Mountains with a school trip. Sure, he gets stuck in a smelly garden shed with the principal, but he's ready to relax. Unfortunately, two campers go missing almost right away, and all signs point to a sasquatch on the loose. In between dealing with Boyle, the school bully, and Archer, a foppish, British monster hunter, Max tries to figure out what creature is responsible for the disappearances as well as the murder of a reporter. After an encounter with a brownie, Max doesn't think the sasquatch is responsible, but in his investigations, he comes in contact with a lot of other monsters, which need to be dealt with. In the end, the culprit turns out to be a very vicious satyr who has a surprising disguise, and Max finds out that he is being targeted by forces of evil.