Youko Asagiri has harbored a secret crush on a classmate for over a year and a half. She writes a piano piece to express her feelings, but when the moment arrives, she loses her nerve and falls through the ground.
Suddenly, Youko finds herself in the mysterious world of Ashanti. There, she meets a talking dog named Lingam, who explains that Ashanti is a twin realm to Noa, Youko’s home world. Once connected, these worlds were separated by the warrior Leda to protect Noa’s people. Youko’s unexpected arrival has temporarily reopened the link between the two realms, attracting the evil forces of Zell, who want to make this connection permanent.
The villains from Zell steal Youko’s cassette player, believing it to be the legendary "Heart of Leda," which is essential to their wicked plans. Youko escapes by transforming into Leda’s warrior form. Armed with her new powers, can she protect the people of Noa and find her way back home?