In the autumn of the third year of Jinglong's reign, Chang'an City was undercurrent. The fourteen-year-old Pei Xijunshang is a boudoir girl. Although she is the daughter of Pei Jian, the Minister of Civil Affairs, she is born with an extraordinary sensitivity to colors and shapes. She can see the dark corners of people's hearts through subtle traces that ordinary people ignore.
A "faceless corpse case" broke the tranquility of Pei Mansion - all seven members of the Chen family of the West City silk and satin merchant died suddenly. The facial skin was completely peeled off, leaving only a strange peony picture on the scene. When Jing Zhaoyin was at a loss what to do, Xijun accidentally discovered that the secret account symbols of Chang'an underground bank were hidden in the painting. Without telling her father, she sneaked into the surrounding temples where the crime occurred in the name of painting murals for Buddhist temples, and actually pieced together a shocking dark network involving the court and the world from the gossips of pilgrims.
As the investigation deepens, Xijun encounters three mysterious forces: the underground gang whose name is "Peony Tattoo", the declining nobles who pursue the art of immortality, and a mysterious organization calling itself "Bone Scavenger". With her extraordinary powers of observation, she traced the indigo dye in the corpse's fingernails to the Persian caravan, identified the household clerk from the account book watermark, and solved an old imperial examination fraud case ten years ago from a nursery rhyme.
When all the clues pointed to the political opponents of his father Pei Jian, Xijun found that he had already become a pawn on the chessboard. In the end, she set up a trap to lure out the real murderer - a person she had never suspected, and uncovered the secrets of the imperial power struggle concealed by the "face-peeling" ritual. The case was settled and his father was transferred to Luoyang. Xijun drew all the case files and put them in the secret box of "Chang'an Mystery Map". She didn't know that when Lu Lingfeng, Su Wuming and others entered Chang'an five years later, this picture would become the key to solving a bigger mystery...
