Sora Aoi is Tsumugi, a typical Japanese teenager—who just happens to be in love with her teacher, Katagiri. Tsumugi seduces Katagiri and he falls for her. But at the same time, Tsumugi is attracted to her classmate, Kosuke, and soon she’s trapped in a love triangle. Now Tsumugi faces a dilemma: Who will she stay with?