Sugiura is a middle-aged man who was unmarried until he turned 40. He used to live alone in a detached house, but he ended up living with two women who were not related to him by blood, his wife and stepdaughter, and his sexual desires only grew day by day. Sugiura has a special fetish for anal, but his wife refuses anal sex, so he is dissatisfied with his marital life. Then, one day...