One is a handsome, indifferent criminal investigation captain (Gu Cun) with a mysterious background, who has repeatedly solved strange cases, and the other is a forensic expert (Su Anluo) who is quiet in appearance but strong in heart. They gather in Xicheng, a city with a very high crime rate. After solving one case after another that was both bloody, cruel and deeply sad, they have always maintained the peace and tranquility of the city.