God's hammer struck twice, punishing the world of Yafaniel below... In the world of Yafaniel, humans and an unusual species called “monster girls” coexist. May Esperio, an Academy student from Kunaguva, is training hard to become a "master" of monster girls with her best friends, Elza and Karen. However, after an encounter with a mysterious stranger, Elza became “Lost” -- a term used for victims of a strange affliction that plagues humans and monster girls alike. Elza and the monster girls in her service have begun stealing the Magus Quartzes that are held in each of Yafaniel's major cities. May decides to travel the world pursuing Elza in an attempt to cure her. However, May knows that if she fails to save Elza, the whole world may be destroyed!