Long, long ago, there existed a world of magic and science. But having both powers was making people conceited and lazy. So God split the world in to the world of science, Erde (German for Earth), and the world of magic, Phandavale. One day in Phandavale, a terrible witch named Cendrillon revives. Cendrillon plots to rule both worlds, and searches for the "key of Erde" and the "key of Phandavale" which holds tremendous power.

A young boy from Erde by the name of Sōta meets a mysterious girl from Phandavale, Akazukin (Red Riding Hood), and her talking wolf companion, Val. Sōta learns that he is the key of Erde. Now it is up to Akazukin, Val, and the other Musketeers, Shirayukihime (Snow White) and Ibara (Sleeping Beauty) to protect Sōta from Cendrillon and her Nightmarians who wish to obtain the power he mysteriously possesses.