Eriko's mother, Mahiru, who has raised her beloved daughter by herself, got married and has finished raising her children. She was supposed to have a happy marriage, but after a while she was consulted by Tatsuro because of Mahiru. When she called him over and asked about her situation, she suddenly confessed, "I like her mother-in-law." Since that day, Eriko begins to be played with as an outlet for his distorted affection. She persuades Tatsuro that this cannot go on forever, but...
