陆兆国如意万事坊女掌柜乔蔓蔓（黄日莹饰）因一桩生意委托错嫁进瑾王府，与“瘸腿”王爷傅承瑾（官鸿饰）从欢喜冤家到携手化解危机，共同对抗二皇子傅云诺（汪卓成饰）和西麟国王子胡尔萨（李耕耘饰），而另一边，本该嫁给傅承瑾的西麟国和亲公主阿里娅（宋霄瑛子饰）却阴错阳差地被身患恐女病症的万事坊二当家纪墨收留，最终两段错位情缘终成眷属。

Framed as the notorious Night Devil on his wedding day, top detective Xiao Beiming is accused of murder and treason, forcing him to flee. Three years later, he returns to the capital, earning the trust of his apprentice sister, Zhong Xueman. With a team of fearless allies, he unravels a series of mysterious cases, to expose the real Night Devil and restore order to Da Qi.