The Spook's Mistake: Book 5 by Joseph Delaney
'The moment of danger is close. Very soon our enemies will be here.' As danger increases, the Spook sends his apprentice, Tom, to be trained by another spook whose methods are harsh and tough. But faced with a powerful water witch, Tom's new master makes a fatal mistake, leaving Tom to face his enemies alone. Can the Spook get there in time to save Tom? Together can they beat such terrible dark power? And will the Spook's own mistakes give final victory to the dark? The fifth chilling tale in the Wardstone Chronicles, the series that inspired the forthcoming movie The Seventh Son, starring Jeff Bridges, Ben Barnes and Julianne Moore.