Yun Mingji, the youngest member of the former Tai Hospital, was framed for poisoning due to a medical case in the East Palace. He lost the meridians of his right hand and was expelled from the capital. Ten years later, he lived in seclusion in Nancheng under the pseudonym "Yun Kai" and lived as a doctor of "Baicaotang". During the day, he diagnosed diseases for the neighbors, and at night, with his superb medical theory and poison identification skills, he quietly solved the mysterious cases that the government was avoiding, just to wait for the truth to be revealed when the clouds opened.
The owner of a silk and satin shop goes crazy, the embroiderer hangs herself to hide poison, the scholar suddenly dies and becomes stiff... The strange cases that have happened one after another in Nancheng all reveal traces of poisonous techniques similar to those in the East Palace medical case back then. He was forced to interact with Su Tong, a philistine but kind-hearted grocery store owner, Liu Zhiqing, a lame former criminal clerk, and Lu Qingwu, the new head catcher who is simple and honest. From suspicion to trust, the four people pieced together clues during the investigation: these cases all point to the powerful King Rui in the capital - the real man behind the East Palace case.
When King Rui's power extended to Nancheng, arson, frame-ups, and serial drug rackets followed one after another. Yun Kai's true identity was exposed, and his companions were also in crisis. He finally understood that pursuing the truth was not only about clearing his own grievances, but also about bringing justice to all the innocent people who had been crushed by power. With his left hand applying an acupuncture to save people, and his right hand holding a medicine pestle to hide the edge, Yun Kai and his companions used medical science as their blade and friendship as their armor to tear a crack in the shadow of the powerful, and finally let the conspiracy of ten years ago surface.
