Mei Shiqi, a junior guard of the Yu Dynasty's Hidden Guard Bureau, dreams of achieving marriage autonomy and freedom through promotion and salary increase. During the investigation, she encountered Leng Moyan, the sinister and vicious Chief of the Inspection Department. The two suspected and hindered each other during the investigation, causing a lot of chaos and thrilling mistakes. After encountering many life-and-death situations and mutual support, they gradually began to trust each other. The two joined hands sincerely to track down the real culprit of the crime that endangered national security and the safety of the country. In the process of fighting wits and courage with the mastermind behind the scenes, they fell in love and killed each other, and finally determined that the other was the love of their life. The two are in different classes and have different secrets and missions, but in the face of life choices of punishing evil and major issues, they can highly unify their personal happiness with national security and the safety of the country, showing admirable wisdom, courage, responsibility and other noble qualities of outstanding young people.