Criminal investigation expert Sun Chengxuan was forced to review an "iron case" from seven years ago, only to discover that the "perfect murderer" he personally sent to prison might not exist at all. As the old case was reopened, all the evidence began to prove against the case handling team back then, including himself. A hunt for the "truth" has quietly begun, and the boundaries between the hunter and the prey are completely blurring out of control.
