After suddenly dying, modern forensic pathologist Shen Weiwan is reborn as a disgraced concubine confined to the Cold Palace in the Great Yin Dynasty. Needle marks on her wrist and arsenic in the corner of her room reveal that she has been made the scapegoat for the poisoning of a royal heir.
She uses her forensic expertise to break the case wide open: testing poison with a silver hairpin exposes a plot at a birthday banquet, examining lividity clears her name of a false witchcraft accusation, and a toxin profile uncovers the truth about the emperor's poisoning years ago. The cold-faced emperor Xiao Che goes from suspicion to affection, but she has no desire to vie for the position of empress. She vows to uncover the cause of her mother's death and the secrets hidden in an old handkerchief from the previous dynasty.
A chain of palace murders unfolds, with every corpse a pawn in a political game. Using her autopsy knife as a blade, she carves out a path for herself within the red palace walls, and establishes an ancient forensic bureau so the truth can no longer be buried by imperial power.
