Li Wu, a clever conman, inadvertently becomes a member of the Imperial Secret Police due to a misunderstanding with Lu Zhen, a cunning guard. With the court in turmoil and loyalties divided, has Li Wu bitten off more than he can chew?

Li Wu comes from a lowly background but due to a misunderstanding, becomes a member of the Imperial Secret Police known as the Embroidered Uniform Guards. On the outside, he appears to be selfish and well-spoken, but deep down he’s honest and treasures brotherhood. Lu Zheng is an original guard; aloof and lacks good speech.

But through their meeting, they find the friendship both have been looking for and evolve together. Together, they are pulled into many cases and hatred that runs deep in the court. Will they be able to solve all of the puzzles without becoming targets themselves?

In the third year of Jianwen, Li Wu, a petty thief from Ji’nan Prefecture, saw Wang Kegong enter Nanjing with his family’s fortune. He thus stole the name card of Li Dongfang, a famous clothier, to infiltrate Wang Kegong’s house, in order to steal his fortune and become rich overnight.

Unexpectedly, Li Mu got entangled in a dispute over the firearms of the former dynasty that revolved around the Fish Lock, and Li Mu, who was initially an outsider, became the holder of the Fish Lock, caught in the center of the whirlpool.

As a child, Song Zhen, the child who rescued Li Wu from the imperial prison, has now become Lu Zheng, an Embroidered Guard and Li Wu’s colleague, but they do not recognize each other; Shu Tang, a girl who was once in the same cell with Li Wu, has become an assassin, and has become a spy couple with Li Wu to complete the task.

The darkness and cruelty of the dynastic strife put the feelings between the three to the test in a series of intrigues like locks. When the moment of dynasty change comes, all the battles and unresolved mysteries will come to an end.