Cat Peters just transferred to Darkmont High and is already desperate to get out. When she hears that Grimoire, the private school nearby, is offering scholarships to the winners of a Halloween soccer match, Cat jumps at the chance. Her little sister, Sookie, and their bookworm neighbor, Jasper, try to tell her there s something ... "just not right" about the old school on the hill, and their worries are confirmed when they uncover a mystery about an entire soccer team that disappeared many years ago. Further investigation leads Cat to a book about ancient Celtic myth and fairy lore, and she soon realizes that there is something truly wicked at work inside the walls of Grimoire.