Wu Zhengzhu (Gan Yucheng) is an experienced and calm old detective. He has been in the workplace for many years, experienced countless ups and downs, and seen countless big scenes. He has already mastered the ability to remain calm even if Taishan collapses in front of him. However, one day, when Wu Zhengzhu came to the crime scene and stood in front of the victim's body, he could no longer remain calm and choked with heartbreak, just because the dead were his beloved wife and daughter. Once, Wu Zhengzhu's wife Jixian (Lee Seungmin) was the only survivor in a terrible murder case. She and Wu Zhengzhu also got married because of this case. Now, Jixian has not been able to escape the call of death, and Wu Zhengzhu has deeply bought the seeds of revenge in his heart. The suspect was arrested, but he could not be prosecuted due to insufficient evidence. The painful and angry Wu Zhengzhu decided to use his own hands to execute the judgment of justice.