Hatanaka Kosaku is a talented boxer who turned pro at the age of 19, winning his debut match with a first-round KO. He is talented, but he has no guts. His uncontrollable appetite is an even bigger problem. He can't put himself in the right weight class, he runs out of energy because of hunger, and he gets knocked out while his eyes are set on food at the ringside. However, Kosaku's life changed when he met Sister Angela, a novice nun in the convent near his boxing gym. She became the source of his power, and Kosaku fights only to win her heart.
Joe Yabuki is an aimless young man who runs away from an orphanage with no money and no place to stay. He runs into a former boxing trainer, Danpei, who still has a strong passion for boxing. Danpei watches Joe fight and regains his desire to train future boxers. Joe, however, does not have any interest in boxing until he ends up in a juvenile prison where he meets Rikiishi, a former boxing prodigy. They quickly develop a rivalry, and a newfound interest in boxing overcomes everybody in prison, including Joe.
