Why does the door at the back of the old classroom keep opening? Who keeps writing on the blackboard in wobbly badly-spelt writing? Frankie Ruggles can’t spell. He struggles with reading and writing, but determined to prove he’s not thick, he sets out to solve the mystery.

When he meets the ghost boy, and sees the red weals on his left hand, left-handed Frankie feels a strong bond. Can he do what the ghost boy wants, get revenge for the cruelty he suffered, and rid the school of a terrifying teacher?