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.

Provides insights into the life of Grimalkin, one of the deadliest witches in the country, if not the world, whose uneasy truce with the Spook's apprentice, Tom, unites them against the ultimate evil of the Fiend.

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.

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.