Things can never be the same again.

The Spook and his apprentice, Thomas Ward, have returned to the county after a long journey and a hard battle. But their troubles are far from over. Their home has been over-run by enemy soldiers. The Spook's house is in ruins, the boggart protecting it has fled, and the malicious witches imprisoned in the gardens have escaped.

Tom, Alice, and the Spook must flee, too, across the ocean to the island of Mona. And it's on Mona that this small band fighting against the dark will face an old enemy grown terrifyingly powerful. Will they be able to vanquish an evil that crawls beneath the ground itself? At what cost?

Will Tom and the Spook ever be able to return home?

"I'm coming for you, and nothing living or dead can stop me."

One witch is the most feared, the most ruthless, and the most deadly of all the witches in the county. If she hunts for you, she will find you. If you have crossed her, you don't stand a chance. She is the witch assassin, and her name is Grimalkin.

Grimalkin's one alliance is with Tom Ward, the Spook's apprentice. With Tom, she plans to rid the world of the most terrifying evil, the Fiend, who once did her great wrong.

For the first time, fans of the Last Apprentice series will hear the story from Grimalkin's side, as she is hunted herself by creatures of darkness set on revenge.

Grimalkin has never been defeated. But can she survive an enemy created for the sole purpose of destroying her?

A dangerous few months lie ahead—ones which some of us will be hard-pressed to survive.

Thomas Ward has served as the Spook's apprentice for three years. He has battled boggarts, witches, demons, and even the devil himself. Tom has enemies: The Fiend stalks him, waiting for a moment of weakness. The terrifying Morrigan, goddess of witches, warned him never to step foot on her homeland, Ireland.But now war has consumed their own country, and Tom, his friend Alice, and the Spook must flee to Ireland. The dark rages strongly there. No one can be trusted. Can Tom defeat the creatures that hunt him most fiercely?