When martial arts master Tang Shan Clan is murdered, his student Yeun (Jackie Chan) sets out for revenge. Travelling to the village of the murderer with the pretty young widow in tow, Yeun discovers that the killer has been overcome with guilt, to the point of self-mutilation. Abased before the widow he confesses and begs for forgiveness. Meanwhile Yeun, whose reputation as a kung-fu master proceeds him, has been drawn to the attention of a local warlord Wei who doesn't take no for an answer. Wei controls the supply of a drug that can save the young widow from a deadly medical condition however, forcing Yeun to reconsider the warlord's offer.

Tang How-yuen (Jackie Chan) is a disciple of kung fu master San-thye. San-thye wins a martial arts tournament, only to be killed by evil kung fu master, Master Li (Yen Shi-kwan). Tang tries unsuccessfully to fight Chung, and leaves the evil master unharmed. Tang, along with San-thye's wife and daughter head after the killer to seek revenge. When they find him, Chung has repented and has cut off his own leg as penance. The master's widow becomes ill, so Tang goes to work for a gang in order to get her medicine. However, whilst in their employ, he is blamed for the death of a young boy, and San-Thye's widow is poisoned. Tang and the one-legged master join forces to defeat the evil lord who poisoned San-thye's widow.