Wolf Boy is sent on a Task by Aunt Zelda, while Septimus and the dragon, Spit Fyre, fly off to bring their friends home, but they all wind up on an island whose secrets are as dangerous as its inhabitants.

With the UnRaveling threatening to destroy the kingdom, Tod embarks on a dangerous journey to find a new Keystone that may have the power to save the castle and its Magyk.

Septimus must battle the remnants of the Dark Domaine, which will remain until the power of the evil Two-Faced Ring is destroyed forever. To accomplish that, the ancient Alchemie Fyre must be relit -- a task that sends Septimus to the very origins of Magyk and Physik, testing both his skills, and his loyalties to ExtraOrdinary Wizard, Marcia Overstrand, and Alchemist Marcellus Pye.