Taichi has long harbored romantic feelings for Yumi, Kouta's mother. One day, when he visits Taichi's house, he catches Yumi indulging in masturbation. Witnessing the scene, Taichi feels both shock and arousal, and his previously pure affection becomes tainted with a sense of betrayal. Overwhelmed by intense emotions, Taichi suddenly attacks Yumi. Years of pent-up desire explode uncontrollably, twisting his feelings into something dark and distorted.