Twenty years ago, my father made a woman and went out, and Kyoko and Toshihiro lived together. Kyoko worked hard and Toshihiro became a good member of society. Toshihiro, who gave Kyoko a hot spring trip for the first time, had a certain determination. "When I grow up, I'll marry my mom." Toshihiro became an adult, remembering his childish promise, and eventually fell in love with Kyoko as the opposite sex.