The Spook and his apprentice, Thomas Ward, rid the county of witches, ghosts, boggarts, and other creatures of the dark. And there’s some unfinished business to attend to in Priestown. Deep in the catacombs lurks a creature the Spook has never been able to defeat. The Bane! But the Bane is not their only enemy. The Quisitor arrives, intent on hunting down anyone who meddles with the dark. Thomas Ward and the Spook must prepare for the battle of their lives.

As the weather grows colder and the nights draw in, the Spook and his apprentice Tom Ward must be even more vigilant in their battles against the boggarts, witches, and ghosts roaming the county. When they receive an unexpected visitor, the Spook decides it is time to move to his winter house in Anglezarke. It is a bleak, forbidding place, full of witches and secrets. Tom hears rumors of menacing creatures stirring on the moors nearby, including the evil beast called Golgoth. Who was the mysterious visitor? And is Tom prepared for what he will find in Anglezarke?

When witches steal Tom's inheritance and kidnap his relatives, Tom, the Spook, and Alice set out for Pendle Hill, a particularly dangerous district, in hopes of preventing the three witch clans from uniting to raise the Fiend, the Devil himself, thus bringing about an age of darkness.

"You can't make alliances with witches and suchlike and hope to avoid being drawn toward the dark." As the Spook's apprentice, Thomas Ward's first duty is to protect the County from ghosts, boggarts, and other dangerous creatures. But now his mother has come back from her homeland to seek his help. One of the most dangerous of the old witches, Ordeen, is about to return to earth, bringing with her suffering and devastation. Tom's mother has mustered a powerful army—including Tom's friend Alice, the Pendle witches, and the assassin Grimalkin—to confront Ordeen. If Tom joins them, the Spook will refuse to take Tom back as his apprentice. What sacrifices will be made in the battle against the dark?