On the planet Music, families of instruments get angry when the Treble, Bass and Alto keys mysteriously go missing. Chaos breaks out, as each instrument plays on its own and no one wants to listen to the grand orchestra. Piccolo, a woodwind, becomes best friends with Saxo, a brass, and the two decide to search for the keys along with Do. A magnificent adventure ensues, full of traps and dangers on a trying search for harmony.