Rin and Aoi are twin siblings, a brother and sister who share a very close bond. Aoi is well-known within her school's kendo club, whereas Rin attracts the attention of girls because of his fashion sense. When a former acquaintance from a rival kendo team shows up, defeats Aoi, and subsequently displays romantic interest in her, Rin experiences a strange sense of jealousy. Aoi fails to comprehend Rin's actions and remains unaware that Rin possesses knowledge about her that she herself lacks...