Even if trapped in darkness, one will always search for the light.

This is a story of a young police officer searching for the answer to Who am I?

Xie Lanshan was an undercover drug enforcement officer who made his way inside the Golden Triangle's most feared armed organization as the right-hand man of drug lord Mu Kun. After successfully returning to his post from the operation, an accidental case of police misconduct triggered a series of unexplainable headaches and hidden memories that began haunting him.

While investigating the truth behind his father's death many years ago, Xie Lanshan utilizes his unique and sharp thinking from the perspective of a psychotic murderer to solve difficult cases around him. Plagued by this growing change and instability of both his mental health and personality, he will later meet a mysterious forensic sketch artist named Shen Liufei. Together, the two men will maintain a strange relationship; as friends and enemies, they solve mysterious cases one by one.

But, perhaps, there was another motive for the forensic artist to approach the young officer...