it was the ropes that made her know the pleasure of sex for the first time. the pain and humiliation of being bound awaken her masochistic libido. a lewd body that becomes sensitive when tightly bound and gets wet when humiliated. mahiro, who peeks at her mother and stepfather's sm sex. mahiro, who becomes interested in tight binding after seeing her mother's blissful expression while bound, masturbates. while her mother is away, she is scolded by her stepfather for peeking and punished. that leads to further training, and mahiro falls into the world of rope bondage.