Medical woman Su Qinglin's father was murdered by Defense General Lu Yun and concubine Meng Yan. She assumed a false identity to enter the General's Mansion to investigate the truth. Aided by a spirit magpie, she discovered that Meng Yan was a snake demon, subdued a white tiger to become a concubine in the mansion, and joined forces with imperial physician Gu Yunze, whose family was killed by the snake demon, to exterminate demons. During the full moon demon-subduing, Lu Yun favored the snake demon, causing Gu Yunze to meet his doom. Su Qinglin uncovered Lu Yun's plot to seize the demon core and build a private army to rebel, secretly cooperating with the emperor to alienate Lu Yun and Meng Yan. After Meng Yan's defeat and demise, Lu Yun swallowed the demon core and lost his mind. On the day of the grand wedding, Su Qinglin exposed all the plots in public, the wrongdoers reaped what they sowed, and past injustices were vindicated.