When his father remarried, Yui, who is about the same age as him, became his stepmother, and the son was excited. Yui showed off her sweaty crotch and made obscene appeals to the son, as if to provoke him. The son picked up some of Yui's pubic hair that he had found lying around, and was about to masturbate in his room while smelling it when suddenly Yui appeared. The son was flustered, but he confessed that he was fascinated by Yui's pubic hair.