The popular doujinshi Gonza's original work "The Day I Straddled My Son," which depicts the obscene immoral sex between a mother and son, has been made into a live-action film starring exclusive Ririko Kinoshita! One day, Mifuyu finds an erotic video of her genitals being played with on her son Natsuki's phone. When she questions him, he says he filmed it as an order from his friends to play around... In order to protect her son, Mifuyu appears in various shoots, including blowjobs, cosplay, and the insertion of foreign objects. Before she knows it, the desire to cum on her son's dick wells up from deep within her body...