Gam yuk fung wan (1987)

Lo Ka Yiu, a young ad designer who is sentenced to jail for manslaughter, has gotten himself in trouble with the corrupted wardens and fellow inmates of Triad background. Chung Tin Ching, a veteran inmate and Yiu's mentor, is forced to confront his comrade's enemies time and again, leading up to the final showdown with the head of security.