Ten years into their marriage, the Fukii couple embark on a long-overdue hot springs trip arranged by her husband. He seems unusually nervous, as if hiding something. That night, while enjoying a kaiseki dinner and drinking sake, Rena suddenly loses consciousness. When she awakens, she finds herself imprisoned in a dark, cold dungeon. The facility's warden, Oshima, informs her that she has been sold to pay off her husband's debts. Oshima commands her to serve as an anal slave, forcing her to endure the humiliation for her husband's sake.