Anna, a typical teenager in the summer before her senior year of high school, wakes up to find her surroundings have drastically changed. While exploring the newly changed landscape of her hometown, Anna suddenly finds herself transported into a whole other world. 

That's when she learns that she was born with special powers and the title Princess of Heart. As the prophesized ruler of the new world, Princess Anna's destiny is to destroy the demons that have plagued her people and to restore harmony. 

When it appears that Princess Anna is about to lose her first solo battle, Twilight, a gifted young swordsman, comes to her aid. Will his mysterious origin and his affiliation with Damien, Anna's most evil opponent, help or hinder her calling?