Maki, who was living a peaceful daily life with her husband and son in a family of three, experienced a drastic change in the mother-son relationship when her son accidentally witnessed the couple's intimate night. 'Because I saw my mom's erotic figure, I can't get an erection!' her son constantly asked his mother for sexual relief. Knowing it was wrong, Maki still couldn't help but comply. And finally, they crossed a line that should never be crossed. 'What is this... Son's dick feels good...'