Tom is dismayed when his master the Spook decrees that they will be spending the winter on gloomy and forbidding Anglezarke Moor but soon discovers the reason for his master's decision, as they tangle with two dangerous witches and struggle to keep a dark mage from resurrecting an ancient evil.

"Alice Dean's destiny is intertwined with Tom Ward's. But he's going to be the next Spook, and she's a witch--possibly the most powerful one the county has ever seen. To rid the world of its greatest evil, the Fiend, Alice will venture into the depths of the dark"--

Now thirteen years old, Tom Ward continues his apprenticeship with the Spook as they confront a dangerous bane who can control people's thoughts.

Apprentice Tom and the Spook for whom he works flee to Ireland, where a powerful witch has joined forces with the dark mages trying to call forth ancient powers to destroy Tom.

"Fifteen-year-old Billy guards a castle prison. But it isn't just criminals he'll be guarding--the ghosts of executed prisoners haunt the place"--

As creatures of the dark hunt for the witch assassin Grimalkin, who carries the captured Fiend's head, Spook's apprentice Tom tries to find a way to finish this terrifying evil once and for all.

Returning from Greece, Tom and the Spook find that their home, including the Spook's precious library of knowledge, has been burned to the ground, and that their battle against the denizens of the dark must continue.