A friend's father vanished, and since there were no children, the friend adopted one of the twins they had given birth to. The son also grew up and went to university. The son found out his real parents while applying for a passport to study abroad. Hibiki, following her friend's advice, went on a trip with her son to talk calmly. The son, knowing he had no blood relation, started seeing the mother who raised him as a woman. In an onsen, the son, aroused by the beauty of his attractive mother, took Hibiki's hand and made her jerk him off. Naturally, Hibiki... freed from reason and taboo, surrendered to pleasure in this incestuous tale of a stepmother and son.
