In the last episode, the director revealed the answer for the audience. The boss behind the scenes is actually Zheng Jiong. There are many murders in the TV series Trace. These murders are not unrelated. After looking at the clues left at the scene, the police found that these cases were related. Who is the real murderer? The bad guys seem to have been watching all this behind the scenes. The drama "Trace" is actually very easy to understand, that is, several policemen in the major crimes unit look for the truth and the real murderer according to the clues left by the murder scene. The hero is a forensic doctor and the heroine Liang is an expert in criminal psychology. When they work together, they often find some important details and then look for the truth according to these details.