For a year and a half, Youko Asagiri has harbored an unrequited love for one of her classmates. To express her feelings, she composes a piano solo that she intends to share with him upon confessing. However, when the moment arrives, Youko lacks the courage to speak to her classmate, and the ground suddenly swallows her up! In an instant, Youko finds herself in the mysterious realm of "Ashanti." She quickly befriends a talking dog named Lingam, who explains that Ashanti is a sister realm to "Noa," the world Youko originated from. The two worlds were once connected, but they were separated long ago by the warrior Leda to protect the people of Noa. Now, Youko's arrival has temporarily opened a path between the realms, which the evil forces of Zell intend to make permanent. The forces of Zell steal Youko's cassette player, believing it to be the mythical "Heart of Leda," an artifact necessary for their nefarious plans. However, Youko manages to evade capture by transforming into Leda's warrior. With these new powers, will she be able to protect the people of Noa and return to her own world?