OBA-354 From today, this person is your mother. Shimazaki Kasumi.

One day, my father brought a woman and said, "From today, this person is my mother-in-law." I couldn't take it and asked her friend Satoshi to harass her. But I never thought he would do something like that. Satoshi had sex with her mother. I couldn't forgive him and had a fight with Satoshi. He wasn't a match I could beat, but I couldn't forgive him. And my girlfriend's mother-in-law, who saw me covered in bruises after losing the fight, kindly healed me. Not as a son-in-law, but as a man...