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

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

As sixty-year-old John Gregory reflects on the past, he reveals how the world of ghosts, ghasts, witches, and boggarts was exposed to him and he later became the Spook, even though his first intention had been to join the priesthood

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.

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