Liu Xi, a modern trace examiner, was repairing a painted bronze mirror from the Tang Dynasty in a museum when he was caught in a sudden burst of blue light from the mirror. His soul traveled to Chang'an during the Kaiyuan period and became Axi, a young widow from a poor family who made a living by doing autopsies for others. As soon as he landed, he came across the unsolved "Oiran's hanging case in the secret room" of Dali Temple. The special pollen in the fingernails of the deceased and the unnatural strangulation marks on the neck were all contrary to the official conclusion of "suicide". Liu Xi resisted the pressure of "women cannot be errands" and used modern trace science knowledge to dismantle the crime scene, accidentally attracting the attention of Dali Temple Shaoqing Xiao Che. From then on, she wandered between the city and the palace walls of Chang'an, from the poisoned cake case during the Cold Food Festival to the "ghost ship" case of Hu merchants in the West City. Every time she solved a strange case, she got closer to the secret of time travel behind the bronze mirror, but she also found that she was being involved in a dark vortex related to the royal bloodline.
