My wife's mother

Her beloved daughter, Mahiru, whom she has raised on her own, has now gotten married and her mother, Eriko, has now finished raising children. It was supposed to be a happy marriage, but after a while, Mahiru asks Tatsuro for an affair. When I called him and asked him about the situation, he suddenly confessed, "I like your stepmother." Since that day, Eriko has begun to be toyed with as an outlet for his twisted love. He convinces Tatsuro that this cannot last forever...