In the last years of the Yong Dynasty, natural disasters occurred frequently, vassal kings separated their regimes, and the Mysterious Medicine Alliance monopolized medicinal materials and used poison for personal gain. The people of the world were in deep misery. Shen Yan, a young man from Qingchuan Township, inherited the legacy of a reclusive medical monk and went down the mountain with Mo Lin, a spiritual snake. He carried a handbook of "Taoism, Confucianism, Buddhism, Dharma and Medicine", and he braved the troubled times with the benevolence of a doctor. He transformed into "Mr. Shen" and guarded Yunzhou Jishi Hall, providing affordable medical treatment to the people; he pretended to be "Mr. Mo" to treat powerful people by letters, and secretly investigated conspiracies; he acted as a "ghost doctor" and went to the battlefield to save soldiers, regardless of fame or fortune.
Liu Canglan, the leader of the Xuan Yao Alliance, is ruthless and colludes with the King of Xihai to develop "corpse poison" in order to subvert the world. In order to thwart the conspiracy, Shen Yan went deep into Black Wind Mountain to explore the poisonous nests and fight the pursuers. He even got help from Prince Jing, the prefect, the shop owner Lin Wanqing and others. From treating the epidemic in Qingchuan to breaking the situation in Yunzhou, from investigating secrets in the South China Sea to fighting against the vassal king, Shen Yan used medical skills as his blade and his original intention as his armor. In the whirlpool of intrigues and vicious schemes, he gradually uncovered the monstrous conspiracy of the Xuan Yao Alliance, vowing to restore a clear medical way in troubled times and save all people from disaster. One person, one snake, three pairs of vests, and a journey across mountains and rivers to save the world begins.
