The film's time background focuses on Hong Kong in the 1970s. It tells the story of the righteous Independent Commission Against Corruption officer Bai Meigui (played by Xu Dongdong), who was ordered to lurk around gangster Lei Wanhao (played by Xie Tianhua) to collect evidence. After accidentally discovering Lei Wanhao's mysterious identity, Bai Meigui still sticks to her belief and captures the two major underworld groups. It is an extreme story.