Joe Yabuki, a troubled youth with a penchant for solving problems through his fists, showcases his raw fighting talent in the slums of Doya. When he defeats a gang single-handedly, he catches the eye of Danpei Tange, a former boxing coach battling alcoholism. Recognizing Joe's potential, Danpei offers to mold him into Japan's boxing sensation. Initially skeptical, Joe eventually agrees to train under Danpei after a life-saving intervention. Despite his rebellious nature, Joe must learn to embrace discipline and master the art of boxing to navigate the challenges of his new path. As he grapples with personal demons and external obstacles, Joe's journey to boxing stardom becomes a test of resilience and trust in his mentor.