Military physician Qin Zhaoyue disguised herself as a man to follow the army for eight years, saving Crown Prince Mo Chengyuan from the brink of death. Upon returning in triumph, she was falsely demoted and sent home due to her female identity. Her fiance Lu Heng placed top in the imperial examination and, deeming her "lacking in womanly virtue," insisted on breaking off the engagement to marry a fake disciple of the medical saint instead. Just as a gu plague spread across Yuehe Town, Qin Zhaoyue tore off the fake medical saint's mask and joined forces with the Crown Prince to investigate the southern gu disaster. From the watermill to the mortuary's secret room, and from mother-gu showdowns to presenting medicine at court, she used silver needles to break gu sorcery and a benevolent heart to restore peace to the realm, ultimately practicing medicine as a woman to save the world, riding side by side with the Crown Prince back to the border.