Sakiko Mihara, a mother of one child, a very ordinary housewife who can be found anywhere. She had a deep animosity with her son, Minoru. While muttering, Minoru grabs his mother's plump breasts from behind and rubs them. How did this happen? A few days ago, Sakiko had a bad relationship with Minoru's friend Daisuke. Daisuke approached him, but he fell in love with the young and experienced Yarichin Tech, and spent his honeymoon days repeatedly. But one day, Minoru, who came back from cram school earlier than planned, saw him masturbating to Daisuke...