Your heart is like a blade

Xue Yuan, the top assassin of the former dynasty's assassin organization "Nightingale," disguises herself as Xia Shu, the second young lady of the Minister's mansion, and marries into the Ningyuan Marquis's household to assassinate the emperor. Unbeknownst to her, her husband, Pei Yuheng, appears to be a playboy marquis, but is actually the commander of the emperor's secret guards. On their wedding night, both harbor secret identities and test each other, yet they gradually develop feelings for each other as they spend time together. Xue Yuan gradually discovers that Pei Yuheng is not as absurd as rumored, and Pei Yuheng, in turn, falls in love with Xue Yuan during his protection and investigation. When Xue Yuan learns that the truth behind the massacre of her sect was not the emperor's doing, but rather a staged event by the Nightingale organization, she and Pei Yuheng join forces to devise a scheme to wipe out the Nightingale organization from within. In the end, the two shed the shackles of their identities...