Huang Jiang (Anthony Wong) and Qi Xi (Lau Ching Wan), both policemen, are brothers, but their actions are very different. Huang Jiang is upright, but Qi Xi is a sworn brother of the gangster boss Blind Chao (Francis Ng). During an operation, Huang Jiang was forced to kill Qi Xi and Blind Chao, and did not explain the reason afterwards, which made Qi Xi's wife misunderstand him. More than ten years later, Qi Xi's son (Huang Haoran) and Blind Chao's son A Wei (Jordan Chan) grew up and inherited their father's careers to become a policeman and a gangster boss respectively. A Wei has always wanted to avenge his father, and Ke Le also had such a plan before he knew the truth of the matter, but after knowing the facts, he began to have a dilemma about whether to choose black or white.