Ji Bai is a no-nonsense cop, a man of action and Xu Xu is a soft-spoken new recruit from a psychology institute; these two opposites must put their differences aside to fight crime and not drive each other crazy.

A madman is burying bladed weapons in parks all around the city and Xu Xu is on the case; her deduction skills help to uncover a corporate kidnapping.

During a kidnapping sting, Xu Xu uses her skills of deduction to find the right culprit, but it takes Ji Bai's street smarts to figure out the motivation.

Ji Bai and Xu Xu continue investigating, but they have opposing methods: Ji Bai says she'll be dismissed if she does not pass the physical exam.

As the case leads to possible human trafficking, Ji Bai begrudgingly admits that he thinks Xu Xu is actually talented.

With Xu Xu diagramming the clues, Yao Meng apprehending the suspect, and Ji Bai doing the interrogation, the Major Crimes Unit is starting to gel.