Joe Knight's daydreams have turned into a nightmare. The new games teacher, Underwood, is even worse than his predecessor. Joe's best friend is leaving. And the worst of all: his parents have traded in his magical piano.

To get it back from creepy Mr. Riddle, Joe offers to work in his shop. He soon discovers the dark history of the piano, but Riddle is suspicious of his determination to reclaim the worn-out, battered old instrument, and Joe must be careful not to reveal his secret.

After befriending Lily, the two prove a formidable team. A metronome constructed with the piano gives them an opportunity to go back in time and set things on the right track... but its use comes with a warning.

Meanwhile, the Headmaster steps from the shadows, revealing an evil plan that places Joe, Lily and the entire world in grave danger.