Shen Ting, a criminal investigator in a modern major crimes unit, falls to her death while pursuing a killer on a rainy night and awakens in the body of Shen Tingruo, an abused illegitimate daughter of the Chancellor's household in the Great Qi dynasty. Her legitimate elder sister, Shen Qingrou, covets her white-jade pendant and pushes her into an icy pond. As she nears death, she is secretly rescued by Xiao Jueyuan, the Prince Regent entrusted with the late emperor's heir. Xiao Jueyuan campaigned on the northern frontier as a young man and wields power over half the court. He is investigating a major case involving the illicit transport of saltpeter and collusion with the enemy, and the Shen family is implicated, bringing Shen Tingruo to his attention.
Having died once, Shen Tingruo is no longer timid. Drawing on her forensic investigative skills, she reconstructs the truth about her fall into the water through wounds and physical evidence, presenting her proof before the family at Fushou Hall. She also takes years of carefully kept account books to her father, securing her full household allotment and punishing the steward responsible for wrongdoing. While carefully preserving evidence in the form of medicinal dregs that show her aunt was being poisoned over time, she follows clues from an old servant, Sun San, to investigate the secret saltpeter dealings. By chance, she discovers a fragmentary secret seal hidden in the white-jade pendant bestowed by the Empress Dowager.
She meets Xiao Jueyuan at Songfeng Pavilion. After mutual suspicion and probing, the two reach a limited agreement to work together. At the Empress Dowager's birthday banquet, Shen Qingrou deliberately frames Shen Tingruo and forces her to perform in front of everyone. Drawing on ten years of classical dance training in her modern life, she dazzles the entire gathering with a dance as graceful as a startled swan.
After the birthday banquet, the clues gradually come together. Shen Tingruo investigates the traitor within the Chancellor's residence, and the pendant's secrets slowly come to light. Crises erupt both at court and within the household, Shen Chongshan's crimes are exposed, and powerful factions clash in deadly struggles. Shen Tingruo protects those she cares about. She and Xiao Jueyuan also break free of their fates as pawns, and true affection blossoms amid their schemes. Together, they quell the turmoil lurking beneath the surface.
