Mako, who lost her husband, started living with her daughter and her husband. One night, Mako witnesses her son-in-law masturbating in the bathroom after being treated coldly by her daughter. Mako gets excited and masturbates on the futon, but her son-in-law sees her instead. On Sunday, my daughter went shopping by herself. Mako witnesses her son-in-law masturbating again. Mako is confused. The son-in-law confessed his feelings for Mako. Unable to control their mutual lust, the two end up having a relationship. From that day on, his immoral acts gradually became more violent. Mako is tormented by guilt, but she succumbs to the passion of her son-in-law and ends up having sex with him again...
