Justice and evil, police, law and crime, this eternal theme is presented to us through the lives of the people in the legal network. As a senior monitoring officer of the Criminal Prosecution Department, Fang Zhihao (played by Wu Qihua) is extremely principled and extremely motivated in his work. Because of a mistake he once made, he could not sit idly by and ignore injustice. He is hailed as the future leader of the legal community. In the investigation with the police, Zhihao is getting deeper and deeper into it; Yang Weisen (played by Lu Songxian), who has been undercover for many years, has hardly been a policeman for a day. Weisen, who has been struggling in the underworld, initially thought that he could control everything, but as he went deeper into the undercover, his identity became more and more vague, which made him hesitant and painful. The various disputes in the underworld and the pressure from the police, prosecutors, lawyers, etc. who do not know his identity have made Weisen deeply trapped in the quagmire. In addition, the police, lawyers, forensic doctors, etc. are all components of various criminal cases, and people from all walks of life have appeared one after another just to seek the truth.