Reiko is married to the founding family of a large company and lives a wealthy life. - However, her husband is only working and neglecting her family, and recently her sexual desire has dried up. Unlike such a husband, she was attracted to her kind-hearted son, Kosuke. Reiko was troubled by her secret love for her son, but the curse was broken with a single letter. It turns out that Kosuke is a child who was mistaken during childbirth. Kosuke is saddened by that fact. However, he secretly looked at Reiko as a woman, and he couldn't stand it and overlapped his hot and wet lips.