In 1992, a supernatural light and shadow appeared in the Longzong Gate of the Forbidden City. Yanbei University students Dayu, Xiaofu, Luo Yi, and Yanzi were attracted by this incident. They started with clues such as copper whistles and rouge boxes, combined with Qing palace archives, and found that it was related to the unjust case of the six-fingered palace maid Yun Xiu in 1900. The four of them went deep into the Forbidden City to explore the secrets and found evidence such as account books and finger bones in the secret passages of the Cold Palace and Buddhist halls. They uncovered the truth about Yunxiu's persecution by the eunuch Liu Anda and finally cleared him of his grievances.
