As danger increases in the County, Tom is sent far north byhis master to be trained by Bill Arkwright, another Spook. Arkwright lives in ahaunted mill on the edge of a treacherous marsh and his training methods proveto be harsh and sometimes cruel. But he has toughened up many previousapprentices and now he must do the same for Tom and prepare him for the gravestdangers of his life.But when the Fiend sends his own daughter, the ancientpowerful water witch Morwena, to destroy Tom, Arkwright makes an error ofjudgement and Tom finds himself facing his enemies alone. The Spook and Alicerealising his danger, hasten to his aid but will even their combined strengthssuffice in the face of such terrible dark power? And what is the Spook'smistake, the consequences of which might give final victory to the dark?