Riki Oshima, the older brother of Osamu, a third-year elementary school student who is troubled by love, is a superhero known only to those in the know. She says that one day, Yuri, whom Osamu falls in love with, will quit her school. Her reason for this is that the boxing gym run by her father has no promising fighters, and she is going bankrupt. So Chikara joins the gym and tries to save Yuri's father and daughter, but Katsuzo Goge, the national high school heavyweight champion, appears and tries to spar with Chikara.