Joe Knight spends his time daydreaming. It helps him cope with the bullies at his school, particularly the hideous new games teacher, Sirgiman, and the sinister headmaster.

On his 13th birthday, Joe receives a piano that looks like it first gigged at a dinosaur's funeral. Worse, it comes with lessons from Ma Apples, who reminds him of a witch. Joe soon discovers that his piano has magical qualities: combinations of notes unlock portals revealing secrets about the bullies surrounding him.

The use of this knowledge, however, exposes him to dangers he didn't anticipate, and he plans to give up the piano - until Ma Apples convinces him that he has been chosen as its keeper for a reason.

With Joe firmly in the sights of Sirgiman and the headmaster, he finds himself in grave danger. And time is running out if he is to wake up to the challenge, and defeat the evil infecting his school before it takes over the world.