Akihito Kanbara has lived his life as a half youmu, being possessed by the most evil youmu, known as “Beyond the Boundary.” Mirai Kuriyama is a Spirit World Warrior with the cursed blood and is the only one who can defeat Beyond the Boundary. After a fateful encounter, they start to get attracted to each other.
The battle is over, and they can go about their normal lives now… Or so they thought.
With no time to rejoice after miraculously saving Mirai from Beyond the Boundary, Mirai lost all her memories. Akihito, now a high school senior, starts to avoid Mirai thinking it’s for the better. Not aware of Akihito’s feelings, Mirai tries to get closer to Akihito. Then, someone who knows of Mirai appears in front of the two. With Akihito’s troubles in vain, Mirai once again sets forth on a battle that forces her to look within.