Her beloved husband, with whom she met by fate, comes home late, and she masturbates to relieve the loneliness of not being paid any attention to her... Nina, the stepmother, plans to release the void in Kokoro that will never be filled with her stepson Daisuke. Seeking the opportunity, she seduces him with her K-cup huge breasts and dynamic big buttocks, and Daisuke, who is of marriageable age, begins to think of his stepmother as a 'woman'. Daisuke finds his stepmother's panties in the dressing room, goes back to his room, finds her masturbating, and honestly confesses. With her super-big breasts in front of him, Daisuke becomes a man, driven by his rising sexual desire, caresses her greedily, and joins her with a raw insertion. He shakes his hips desperately and has sex with her in a daze! Mother and son, who sneak away from her husband's eyes and entwine day after day, are engulfed in the waves of desire and cannot turn back, becoming in a forbidden relationship!