Hikaru Konno and her younger brother begin living together in the same room, and he finds himself increasingly aroused by her unguarded presence. Constantly catching glimpses of her panties and captivated by her sleeping face, forbidden emotions slowly awaken within him. After secretly watching his sister having sex with her boyfriend, his pent-up desire erupts, driving him to assault her while she sleeps and consummate their incestuous relationship. Initially shocked and confused, Hikaru gradually becomes emotionally entangled as she responds to her brother's intense feelings, ultimately losing herself in their illicit intimacy.