Aimi and her husband move to a city where her brother-in-law lives due to her husband's job. Aimi appears modest and ordinary, but secretly harbors a deep masochistic passion for tight bondage. Her brother-in-law shares the same fetish, and the two are drawn to each other. Their forbidden relationship gradually intensifies, blending sin and pleasure, as Aimi becomes increasingly bound and writhing in ecstasy. Enveloped in the bliss of constricting ties that crush flesh and grind bones, her very soul becomes enslaved. "My body and soul have both been completely bound..."