Please Keep a Healthy Suspicion of the Suspect

Nine years ago, the legendary thief "Night Crow" stole a piece of top-secret evidence and vanished without a trace.

Nine years later, a bizarre locked-room murder bears Night Crow's signature. Xing Xiu, head of the major crimes unit, arrives to investigate and personally requests the help of Li Su, a mild-mannered and composed criminal psychology consultant.

One is skilled at finding weaknesses in people's hearts; the other can see through every disguise by instinct. They work together to piece the case together while secretly testing one another. Xing Xiu gradually realizes that the airtight consultant before him may be the Night Crow he has been pursuing for years. Li Su, meanwhile, realizes that the clues to an old case in Xing Xiu's hands are the only key to finding his missing family member.

When copycat crimes reveal a secret network that rewrites evidence to protect the powerful, the two are forced into a dangerous bargain: they suspect and use each other, yet are also the only way for each other to escape a dead end.

But when all the evidence points to someone close to them, they must decide: will they send each other to the dock, or join forces to bring down those who make the rules?