Synopsis：Su Nuan Nuan is a civilian girl working in the disciplinary inspection department of the Internal Affairs Bureau. She is kind-hearted, quirky, righteous, and courageous—though a little naive. Shen Yu, a scion of a wealthy family, serves as the head of the criminal investigation unit in the same bureau. He is handsome, proud, sharp-tongued, and dark-hearted. To all appearances, they belong to different worlds, but a disciplinary notice sets off an emotional entanglement between them. Shen Yu chases after Su Nuan Nuan to get the notice rescinded, yet in the process, he unexpectedly falls for her. Su Nuan Nuan, however, remains completely unaware and even stays by his side under the guise of his cousin, Sun Mengya, after the latter passes away. Su Nuan Nuan does not realize that she has long developed genuine feelings for Shen Yu. But when Shen Yu learns that Sun Mengya's death is connected to Su Nuan Nuan's uncle, and Su Nuan Nuan discovers that Shen Yu's marriage has long been reduced to a tool for family alliance, mutual misunderstandings arise even as they remain concerned for each other. In the end, they both open their hearts, trust each other, find the real culprit behind Sun Mengya's death, and use love to break free from the fate of an arranged marriage.