Genmu Senki Leda

A high school student named Yohko is in love with a boy unaware of her feelings. She writes a song to express her emotions, but it contains more than just a few strong sections. While listening to the song, she is transported to a parallel world called Ashanti. This song can open a portal between Earth and Ashanti large enough for an invasion. The song was forbidden long ago by a warrior named Leda, who foresaw its danger. Now, Yohko and some new companions must prevent the invasion and restore balance between the two worlds. It seems Yohko may not be as ordinary as she appears.