Living in an impoverished Chinese village, Dr Yang (Yu Rong Guang) is a well known local physician who provides medical care free gratis to the villagers. Looking after the ill and lame is not the only skill Dr Yang possesses. He is also an accomplished martial arts expert and vigilante known as the Iron Monkey, who is the scourge of the local villains. Robbing from the rich and giving to the poor, the Iron Monkey is the toast of the locals but soon makes himself an enemy of the local governor. When a famous fighter, Wong Kei-Ying (Donnie Yen) and his son visit the village, the young boy is captured by the governor. The youngster is held to ransom until his father agrees to dispose of the Iron Monkey. The only way to rid themselves of the evil governor and to secure the release of the young boy is for Wong Kei-Ying and the Iron Monkey to join forces.