With Shanghai in the 1920s as the background, the outstanding detective Tang Lang (Wallace Huo) was involved in one bizarre case after another. In the process of pursuing the truth, he formed an invincible golden partner with Huang Que (Alina Zhang), a female lawyer who returned from England, Xiao San, a "magic hand" in the market, a rich woman with a beautiful daughter, and a gang leader who people hate and love. Since Tang Lang was planted and had to trace the real murderer, the five-person team skillfully threw out one cold case after another, including shady trading case of police station, red star murder case, bizarre kidnapping case of rich man and rare gold murder case. When each cold case was about to be solved, it was found that there was a more shocking big secret hidden behind it.