Joe Yabuki is a young drifter who meets Danpei Tange, a former boxing trainer while wandering through San'ya. Joe is arrested for fraud and is thrown into a temporary jail where he fights Nishi Kanichi, the leader of a group of hooligans. He and Nishi then go to the , a juvenile detention center miles away from Tokyo. There Joe meets Tōru Rikiishi, a former boxing prodigy, and a rivalry develops between them after Rikiishi stopped Joe and Nishi from escaping the prison. They attempt to resolve the rivalry by facing each other in a boxing match in which Rikiishi dominates Joe until the latter hits him with a cross-counter, resulting in both being knocked out. Feeling that the outcome of the match did not resolve anything, Joe and Rikiishi vow to fight again. As Rikiishi learns he is meant to leave the prison, he challenges Joe to a fight in the future, and the two promise to meet again, this time as professional boxers.