Yu Sheng was diagnosed with a congenital absence of the left hand at birth, accompanied by a slight intellectual disability, and his father, Yu Guangrong, has since said goodbye to the boxing ring and is dependent on him. At first, Yu Guangrong teaches his son to face life with a smile, but Yu Sheng is consistently bullied, so he teaches his son boxing and swings at fate. When Yusheng grew up, he defied his father's objections and stepped into the ring for professional matches and became so famous that he attracted social attention. However, Yusheng is banned indefinitely for violating the rules in the ring. After a few twists and turns, Yusheng returns to the ring, determined to fight not only for himself, but to fight for the underprivileged with his fists, and to do right by people with disabilities.