Deadly Strike

Deadly Strike, also known in the West as Breakout from Oppression, is a 1978 Hong Kong martial arts action film directed Lau Karleung and his adopted brother Gordon Liu, the latter helming his directorial debut. Film stars Liu alongside Dean Shek.

In town, a mean man named Au Sanyeh owns a firework factory who treats his workers as slaves while not paying them fairly. To avenge his family, To pretends to help Au against the Cheung brothers who always opposes him. After big fights, To later found out the murderer was actually Sam.The film grossed HK44,954.40 at the Hong Kong box office during its theatrical run fromtoJune 1978 in Hong Kong. ........

Source: Wikipedia