Riho was born the proud daughter of a major company's president, but her father's illness has left the business unstable and her husband exhausted after taking over. Former subordinate Kaneshiro offers the Fujimori family financing, yet Riho despises him for betraying the company and rejects his proposal. When she learns the business cannot survive without his money, she sacrifices her body for her husband and her father's company. Through humiliating anal training, the strong-willed heiress is gradually broken into an obedient slave.