Alma Tandoji, seventeen, keeps others at a distance due to a past incident. One night, Ruri Aiba appears at his door. She pleads with Alma to battle against the Dark Stone, creatures that can only be defeated by the power of the Sacred Seven within Alma.

Theres been a change to Ruris sister, Aoi. Five years ago, as Ruris family, their butler Kagami and his son spend a fun-filled Christmas week together, Ruri and Aoi have a fight. While small in scale, it changes the destiny of the two girls.