During the yellow plum rainy season in Chang'an, a murder in a secret room suddenly occurred in Wanhua Building in Pingkangfang. Shen Zhiyan, the son of the Minister of Civil Affairs, died mysteriously. In his hand, he clutched half a purple jasmine flower and rice paper engraved with the word "Moonfall". The white jade hairpin left at the scene pointed to Lin Xinluo, a medical girl from southern Xinjiang.
Jiang Nianyi, the young minister of Dali Temple, intervened in the investigation and found that the deceased had been poisoned by poison from southern Xinjiang. Lin Xinluo, who claimed to have just delivered the medicine, had half a lotus tattooed on her wrist, and hidden in her sleeve was purple mud that had the same origin as the gold powder in the fingernails of the deceased. She came here to find her twin sister Lin Xinyue, who was kidnapped three years ago. The blood-stained jade hosta was a token of the two sisters.
As the investigation deepened, the secret passage of the abandoned kiln in the west of the city, the tributes in the Dali Temple warehouse, and the secret letters of Prince Zhan Shifu came to light one after another. The map of the trade routes of the Western Regions in the hands of the deceased and the code "at the beginning of July and the sunset of July" are actually closely linked with the longevity poison plot of An Chengying, the governor of the Western Regions. An Chengying used the blood of the twin girls as a guide to refine Gu, and colluded with the East Palace in an attempt to control the government. The disappearance of Lin Xinyue and the tragic death of Shen and his son were all due to this bloody deal that spanned three years.
This is a life-and-death game with Chang'an as the game and poison as the chess piece. It is also an elegy about waiting and reconciliation - the fog locks not only the city, but also the lingering obsession deep in the heart.
