After winning the Anti-Japanese War, Gu Yaodong (Li Yifeng), a top-class law graduate from Dongwu University who grew up in a Shanghai alley, became a Criminal Police Officer with the ideal of "Supporting justice and Protecting the people".

However, Gu Yaodong, who had just entered the workplace, was not only squeezed and suppressed by his colleagues in the Criminal Investigation Division but also involved in the fierce struggle between the Communist Party’s underground intelligence network and the Kuomintang police.

In the chaotic times, Gu Yaodong had to make a choice that was loyal to his beliefs in the confrontation between justice and injustice.

In the end, with the help and training of the Shanghai Underground Party, Xia Jicheng (Wang Longzheng) and Shen Qinghe (Gina Jin), he fulfilled his ideals in the journey of revolution and gained precious love.

About Gu Yaodong, Many people wondered how could he persuaded a top star like Li Yifeng to take on the greenhorn policeman role.

About Shen Qinghe, At first, Wang Wei had no actress in mind, until Li Yifeng recommended Gina Jin to him.

Achieved High scores from many sites; Douban 8.2 points, Zhihu 9.1,[5] Tencent 9.3[6] The series was Top 1 drama with the highest rating during the broadcast.