Mr. Offkey is jealous because he can't sing. So, he steals all the music from the Mystic Garden. The characters in the Mystic Garden decide to visit him, and they convince him he can sing. At first, he doesn't think he can sing, but soon he joins in the song and begins to sing. This changes him completely, and he happily gives all the music back. He then changes his name to Mr. Onkey.

The book contains a description of the cast of characters and simple music exercises.