Yuri lives with her husband, who injured himself protecting her, and his step-siblings. Burdened by guilt, she gradually begins to feel a growing physical desire. One day, she is caught masturbating by the older stepbrother, Yusuke, and is assaulted by him. After experiencing sex for the first time in a long while, she reaches climax repeatedly, awakening her lewd sexual cravings. Yuri soon transforms into a submissive woman completely dominated by the step-siblings.