Transferred to Tokyo, Makoto becomes captivated by his neighbor Eriko Miura, a voluptuous married woman. One night, he hears strange noises coming from her apartment and, following the wall, discovers a mysterious hole. Peering through, he clearly sees Eriko's seductive figure and becomes completely obsessed. Soon, Makoto begins pressing his body against the hole, experiencing sensations indistinguishable from real sex. Awakening to this intense pleasure, his relationship with his neighbor takes a dark and intimate turn.