Yuki, who no longer has sex with her husband, is frustrated. This morning, after masturbating in the bathroom, Yuki heads to her son's room to wake him up, but there she witnesses him masturbating to calm his morning wood. "If only you had told me... I would have made it easier for you..." Yuki gives in to the throbbing in her crotch and bites into the black morning wood she has never seen before... From that day on, Yuki becomes addicted to her son's morning wood, and turns into a dirty mother who enjoys it every day.