At the rural Sakuragaoka High School, an eerie legend known as “Kiriko in the Mirror” has been passed down among the students: if someone who should not be there appears in a mirror, you must never acknowledge them. As students begin disappearing or dying under mysterious circumstances, Natsuki Kiriyama witnesses her best friend, Sakura Yukimura, being killed in the girls’ restroom by a mysterious girl reflected in the mirror. Determined to uncover the truth behind Sakura’s death, Natsuki begins investigating the identity of “Kiriko in the Mirror.” However, the mirror’s curse soon turns its attention toward her as well.