Double Dragon in Last Duel

Ker, an expert in the martial arts gets the job of escorting the government's payroll, and is befriended by a seemingly heroic fighter, Wang, who is in fact the leader of a gang of bandits.
When the chance comes, Wang kills Ker's family and grabs all his property, but the son escapes. Years later, Dragon seeks revenge for the injustice to his father in a duel to the death.