The serious Yokoyama, who runs a construction company, has been married for 15 years and his children have grown up. At that time, her wife's younger sister, Rei, who was busy raising her children, found out about her husband's affair and came to her house, entrusting her child to her parents in order to keep her distance from her for a while. rice field. Yokoyama, who saw Rei milking with a breast pump while talking to her wife, was lustful that she had become an adult woman, and even thought that she wanted to commit.
