During the Yong'an period of Daliang Dynasty, Lin Shu, the daughter of an imperial physician, was rescued by a mysterious "Yi Yin" old man and learned amazing medical skills due to a palace incident that destroyed her family and her family. Five years later, she changed her name and entered the palace as a medical woman, just to find out the truth about her father's injustice.
In the deep palace, she used silver needles as pen and poison as ink to wander among the concubines and powerful ministers who had their own evil intentions. By some strange combination of circumstances, she became the cold-faced King of Hell, the personal medical woman of Lu Hanzhou, the commander of the Forbidden Army. Lu Hanzhou was ruthless and decisive in killing, but he tolerated Lin Shu in every possible way.
When poison and medicine intertwined, love and hate entangled, Lin Shu discovered that his father's injustice actually involved a shocking palace secret. What separates her and Lu Hanzhou is not only the disparity in status, but also the deep blood feud.
Should he kill her, or protect her for life?
