In the fictional dynasty, there is a tradition of "Mirror Sacrifice" - royal members must swear an oath to the "Mirror of the Past" on a full moon night, and liars will be possessed by the "soul" in the mirror. The heroine Su Qingyan is the daughter of a minister of the Ministry of Civil Affairs. She looks very similar to the queen. She was selected by the queen mother to be a "substitute" and sent to the palace. However, she was accidentally involved during the Mirror Festival and exchanged bodies with the queen's soul. The male protagonist, Yong Emperor Xiao Jingyan, appears to be gentle, but in fact he has been wary of the Queen (the daughter of a powerful official) for a long time. After discovering that the "Queen"'s temperament changed drastically, he secretly observed it.
