The Kingdom of Music has always been protected by the Crystal Melody Box. This contains the Sound Jewels, used to spread peace around the world. 

Suddenly, Demon, the Lord of Darkness, destroys the Crystal Melody Box and changes them into the Jewels of Negativity. 

To defeat the negativity and prevent the world from being enveloped in darkness, the Goddess Of Music, gives the Rhythms the task to find heroes, the “Miracle Tunes”, to help them defeat Demon for good.