Sayuki had felt a strong attraction to her older college professor, Sawada, since her days as a female university student, and they married while she was still in school. Their newlywed life began with her accepting his abnormal sexual desires. Years passed, and as Sawada became aware of his declining sexual function, he sought new pleasures, ultimately deciding to have his assistant, Sagawa, take over. Initially repulsing Sayuki, Sagawa gradually captivated her through intense training and his large penis, enslaving her completely. In the process, Sayuki herself begins to develop new emotions.