The story takes place in the present day, where Uncle Nine is the owner of a boxing gym. Many boxers have benefited from his tutelage and promotion, and the most important thing in his life is his endless fighting lessons and meticulous fight theory. Among his theories, the most important one is: self-protection always comes first. Ten years ago, a champion fighter who benefited from Uncle Nine's guidance, Ah Chen, was paralyzed in bed due to a surprise attack by his opponent in a match. Jin Tai is a free sparring athlete who trains in free sparring with Uncle Gou. He understands his goal and knows how to prove his strength to the world, and has a strong desire to win the most prestigious world championship. In reality, the pounding in the ring is far more terrifying than the pounding in the real world.