It's been a thousand years since the Camelot of King Arthur, Merlin, Guinevere, and the Knights of the Round Table. A mangled version of the castle still stands, but under a decidedly dark shadow these days. Hidden in its bowels are deep secrets and miserable prisoners. JoJo Mallory is a troublesome 6th-grader in Ferry Village, Maine, whose father - according to the Leprechaun who appears one morning - is now one of those prisoners. To rescue him, she has to find Merlin's most powerful magical talisman and deliver it to the witch-daughters of Pewtris Grimm. JoJo has two best friends who couldn't be more different from one another: Trip, the young phenom hockey star, and Marcy, the uber-intelligent geeky bookworm. Together, the unlikely trio faces one adventure after another as they attempt to solve the most challenging puzzle of their lives.