Single mother Waka Ninomiya finds herself approaching the end of her child-rearing years as her son Kaito grows up. Still in the prime of her womanhood, she meets a new lover and begins enjoying the pleasures of being a desirable woman once again. However, when she tells Kaito about her desire to remarry, he reacts violently, crying, "Don't take my mom away!"—driving the lover to leave. Overcome by disappointment and loneliness, Waka turns to alcohol. As intoxication clouds her judgment, she begins to notice her son's immature body and a new, unfamiliar side of him, feeling both a subtle smile and rising pleasure. Is it the alcohol, raw desire, or something deeper rooted in maternal instinct? For a son who still needs her, she decides to provide the ultimate sex education—personally guiding him through the intimate lessons of a woman's body, step by step, giving him creampie after creampie in an act of forbidden incest.