The series follows the adventures of three adolescent kids: Cassy, a third-year junior witch, Gus, a half-elf second-year junior wizard, and Verne, a logical kid who can't grasp the idea of magic. The three heroes must go through underground caverns filled with dangerous creatures in order to find the world's missing magic, of course they have a little help from thier book, friend and loyal magical companion U.B.O.S.