Modern pomelo red researcher Su Yunjin, whose patent was stolen by her junior sister and who fell from a building, is reborn as a humble firewood-chopping maid in the Ming Dynasty's prefectural governor's mansion. Relying on modern pharmacological knowledge, she discovers the miraculous efficacy of pomelo red and uses the pomelo red pool water to cure Prefect Xiao Yi's stubborn illness. She roots out medicinal herb corruption, saves the masses in the epidemic area with pomelo red, receives an imperial decree to enter the capital to counter the conservative Imperial Hospital, and shatters the medical monopoly. Her arch-rival from her past life also crossed over, seizing prescriptions with fake Western drugs. Having endured court framed-ups and assassination storms, Su Yunjin establishes a female medical clinic and clears her lover's wrongful charges. Finally, she is conferred as the Pomelo Red Female Chancellor, writing books and passing down skills to make pomelo red medical art benefit the world.