In the 1960s, Hong Kong police were bribed. The profit chain formed by gambling dens, middlemen and the police attracted a lot of money. In ten years, the amount of bribes received by the police reached 10 billion Hong Kong dollars at that time. Kowloon City plainclothes Huo Qilin (played by Anthony Wong) did everything he could to solve the case. Under pressure from his superiors, Huo Qilin went to the streets to pick people up as usual. College student Han Zhibang (played by Alex Fong) was framed and beaten by him. Han's mother asked the old police officer to find the middleman between the police and the gang, Zhu Youzai (played by Wong Jing) to rescue him. Xu Legong (played by Tony Leung), known as Le Ge, was the chief Chinese detective at the time. He was arrogant and generous. Chen Xijiu (Eason Chan) is kindhearted and good at observing people's words and expressions. He is deeply appreciated by Brother Le. In just five years, he was promoted from an ordinary plainclothes officer to the inspector of Shau Kei Wan District. However, one of the prices he paid was that his family took in nine mistresses of the big brothers to hide their tracks... In 1974, the corruption in Hong Kong shocked the world. The Independent Commission Against Corruption was established. Chief Commissioner Yan Guoliang (Lin Baoyi) hired college student Han Zhibang and frustrated police officer Huo Qilin to form the first batch of independent commissioners to crack down on Hong Kong's underground rules. When Chen Xijiu lost his money and his life due to corruption, he unexpectedly found the true love of his life...