Yan Xing, a concubine’s daughter from the Yan family, was trained from a young age by the Ministry of Justice’s chief inspector, acquiring exceptional investigative skills and the ability to find answers hidden within evidence. Yan Xing passes the examination to become a female official in the Ministry of Justice, determined to uncover the true culprits and uphold justice. However, when her third sister flees from an imperial marriage bestowed by the Empress Dowager, Yan Xing is forced to marry in her sister's place to protect her family, tying the knot with Shen Du, the head of the imperial guard. Mysterious cases begin to occur frequently in the capital, and Yan Xing and Shen Du join forces to solve several major cases. As they work together, their relationship gradually deepens. Together with their companions, they uncover a shocking conspiracy and protect the peace and justice of Xiang'an City.