An incest drama presented by a long-established mature woman Ruby. Takeshi's father died 10 years ago, and he has been in an incestuous relationship with his mother, Misuzu, for the past 7 years. As expected, after 7 years, the forbidden relationship will become a rut. One day, when I confessed my relationship with my mother to my cousin Hiroaki, who is in the same situation, I learned that it was the same incest relationship, saying, "Actually, my house is also." Such two people think of a trick, 'Let's exchange mothers'.