Raised in a single-parent household, Noboru is introduced to his mother Ikumi's new fiancé, Kunio. For Noboru, who has long harbored deep feelings for Ikumi, this comes as a devastating shock. Kunio has a peculiar sexual fetish—he enjoys inviting friends over for three-way orgies, a practice to which Ikumi has grown accustomed and even finds a degree of satisfaction. One day, Noboru accidentally witnesses his mother in the midst of such an orgy. Overwhelmed by the painful gap between his idealized image of his mother and the harsh reality, his emotions spiral out of control. Overcome with passion, he ends up taking Ikumi right in front of her soon-to-be husband. Though she initially resists, Ikumi's body begins to heat up in response to Noboru's throbbing cock, and despite stifling her moans, she gradually succumbs to the pleasure.