Yun Shu, a genius surgeon from the 21st century, unexpectedly transmigrates into the Great Zhou Dynasty and becomes the legitimate daughter of the prime minister. She hopes to live a peaceful life, but her extraordinary modern medical skills force her into the stormy currents of court politics.
The story begins with a high-stakes gamble. With a single silver needle, she pulls the dying young imperial grandson back from the gates of death. In one stroke, she makes a name for herself in the capital and is granted the title of county lady, stepping into the very heart of the struggle for power. Soon after, she is invited to treat the chronic illness of the wife of the Marquis of Zhenbei, a man who commands the army. To her surprise, she discovers that the illness is exactly like that of the Leisurely Prince, who supposedly "died of illness" twenty years ago. Both cases stem from a strange, chronic poison called "Orchid Phantom Fragrance."
A shocking conspiracy spanning twenty years and involving both the imperial clan and the military's inner circle now reveals its first sliver. The emperor makes her his blade and orders her to investigate the case, thrusting her into the eye of the storm. As assassinations and poisonings follow one after another, Yun Shu turns their schemes against them, using herself as bait and pretending to be gravely ill while secretly laying her plans. She vows to drag out the viper hidden in the deepest shadows.
She does not fight alone in this contest of wits and strength. Xiao Jinyu, the heir to the Marquis of Zhenbei, seems carefree but is actually meticulous. With medical skills and cunning just as unfathomable as her own, he becomes her most mysterious and reliable ally. Together, they secretly join forces, using ingenious remedies and clever schemes to expose the dynasty's deepest festering wound, confronting the blood-soaked truth buried for so long about imperial power, love, and betrayal.