On the Lantern Festival’s luminous night, Princess Ningyuan died weirdly at the royal banquet. Assigned to this enigma were Li Peiyi from the Inner Surveillance Bureau and Xiao Huaijin, the director of the Imperial Astrology Bureau. Li Peiyi, unmatched in combat and perspicacious in life, aloof but soft-hearted, devoted herself to revealing the truth. To her, each case is more like a match against darkness itself. In the tacit cooperation with the meticulous Xiao Huaijin, they drew out the threads of the cocoon and ultimately dug out the truth and the real culprits through the domineering daughter of a powerful nobleman and the secretive General Lin of the Jinwu Guards.