Introduction
When there is always a 'thirteenth spectator' that no one acknowledges at the scene of a serial murder, former detective Ji Xiao discovers that only he can see that figure. Forensic doctor Shen Jin secretly blocks the evidence, reporter Wen Tang is working step by step, but the figure in the painting of nurse Han Jin is stepping out of the paper step by step. Each of them is related to death, but no one dares to admit that he is the murderer. And those who are truly chosen are those who are destined to witness everything - including Ji Xiao himself.
