Following the tragic death of his abusive father, young Riku Azami finds shelter with his mother, who resides with a dangerous yakuza member. When a violent altercation erupts between Riku and his mother's drunken partner, Riku defends himself by taking the man's life. Witnessing Riku's fighting skills, Kyousuke Tokorozawa, a retired boxer and yakuza, introduces him to the world of boxing. Driven by past trauma and a fierce determination, Riku embraces the sport. Despite his distant facade, Riku uncovers new reasons to fight, including his devoted childhood friend, Yuki Naeshiro. After honing his skills at Baba Boxing Gym, Riku harbors a burning ambition to reach the pinnacle of boxing. Now a seasoned 18-year-old boxer, Riku sets his sights on claiming the esteemed Oriental and Pacific Boxing Federation title, striving to cement his legacy as a boxing champion.