Danny Cloke writes his favorite author a fan letter, only to find out that the author is a ghost, who—for a price—will haunt Danny's wicked stepmother until she repents for her behavior.

Eleven-year-old Danny's ex-stepmother and member of the Society of Librarians Against Youth, Aunt Mildred, has put a Zero Hex upon him, and Danny and his friend Imogen must break it before he is forced to endure a spell behind bars.