Wife's younger sister - Breast milk dripping seen by hidden camera -

Yokoyama, a serious man who runs a construction company, has been married for 15 years and his children have grown up, so he has less sex with his wife and only occasionally goes to sex clubs in the suburbs. At that time, the wife's younger sister Rei, who was busy raising children, found out about her husband's affair and came to the house, leaving the child with her parents to keep some distance between them. When Yokoyama saw Rei milking her breasts with a breast pump while talking to his wife, he became so horny that she had become an adult woman that he even started thinking about raping her...