The Delinquent(1973)

Delivery boy Chung rings an order to a local martial arts school. He shows that he too is a kung fu student when he punches a bag and also kicks out the instructor for his money. Chung has a tough life. His father constantly nags him to work hard. One day, his is heckled by Chien-Pe, a disabled thug who runs a gang. Chung fights and beats them up and as a result, he is fired from his job. Chien turns to his boss, Tai Chung, to get Chung.