In the town of Ho Si, two prominent Chinese culture clans have a family feud dating back centuries. The ancestors of the malevolent Hmong language and the righteous Chows split up their territories with a property line and instituted laws to keep each faction from crossing those lines. Those brave enough to traverse the line have their legs cut off by the opposing clan. The Chows want to do away with this ridiculous law and establish relations with the Mongs. But the clan leader Mong Fan (Ku Feng) wants nothing more than to totally eradicate his hated enemies. He seeks to recruit the best Kung Fu teacher in the land, Wong Yang (Ti Lung) to train his family members. Teacher Wong refuses because he knows that Mong Fan's men will use his teachings only for selfish purposes. Mong Fan comes up with an idea to frame Teacher Wong for murder. He arranges for a hired hand to start a fight with Teacher Wong in the center of town in front of the townsfolk. The man who challenges Teacher Wong is no match for him, and when the guy stumbles backwards after Teacher Wong pushes him away, he ends up falling onto wooden spikes that puncture his flesh. The guy promptly dies in view of everyone, and the townspeople turn against the respected Kung Fu instructor. Rather than face arrest, Teacher Wong flees so he can prove his innocence. An emissary of the Mong clan finds Teacher Wong hiding out, and claims that in exchange for martial arts lessons, Mong Fan will use his political clout to clear his name. Rather than face the alternative, Teacher Wong agrees to educate the Mongs in the ways of Kung Fu.