Yuuya, a curious young boy, sneaks a peek at his crush, Mariko, only to stumble upon a chilling secret: a face speaking from her chest. Intrigued, he listens in again the following night, only to be caught by Mariko herself. Shockingly, she discloses that the face belongs to her late homeroom teacher, supposedly deceased by her hands. Frightened yet captivated, Yuuya embarks on a journey to unravel the mysteries shrouding this bizarre phenomenon.