Zheng Huan is a young male doctor who serves as the antagonist in this section. He secretly copies Lin Nan's medical formulas and then accuses her of using banned books and spreading feudal superstition. Caught red-handed sneaking through her notebook, he doubles down on his accusations, trying to drag Lin Nan down with him. He shouts to the villagers that Lin Nan lacks professional ethics and should not be allowed to treat patients or stay in the village. When the villagers support Lin Nan instead, Zheng Huan quits in anger, leaving a spiteful note on the clinic door. He is portrayed as greedy, self-serving, and vicious when cornered.
