The Lonely Hunter (1981)

Lee Tong (Felix Wong) grew up with only one intent in mind: revenge. After his gangster father died in the hands of friends Fang and Fong, Tong was raised by his father's henchman, trained to be a lone assassin. Coming of age, he finally sets his plan into action and kills an underworld boss. Timid driver Au-yeung Gong (Michael Miu) unwittingly witnesses the crime but is too scared to rat out Lee, leading to an unexpected friendship. Gong ends up helping Tong enter the organization, laying the path for Tong's revenge. As time passes, Tong's cold and lonely front begins to fade as he experiences life, love, and friendship for the time, but Gong is slowly transformed from a naive youth to a cold-blooded killer.