In the 14th year of Tang Tianbao, the An Shi Rebellion broke out. The emperor fled west, leaving the eunuch Chen Jingbian in sole control of Chang'an. Possessing the Night Firefly Map, which holds the secrets of the realm's most powerful figures after their deaths, Chen becomes the target of spies from all directions. At this critical moment, Feng Yinniang, the daughter of a military family, ventures alone into Chang'an. Disguised as a healer, she approaches Chen Jingbian, seeking to seize the Night Firefly Map and uncover the mastermind behind the conspiracy that destroyed her family.