Takuto's wife has been refusing to have sex with him because his penis is too big. Recently, he has been masturbating to adult videos or his stepmother, Mary, to satisfy his urges. One day, Mary, who has always been dissatisfied with their relationship, becomes interested in his enormous penis... Whenever she gets the chance, she makes him ejaculate, using the excuse that she is doing it on behalf of her daughter. Before long, Takuto's daily routine has become one of satisfying his uninhibited stepmother's sexual needs, and he can no longer be satisfied without her body...