After practicing for thousands of years, the snake Yin Dai encountered a scholar named Lu Dongbin, who saved her from a lightning strike, and they fell in love with each other.
However, Yin Dai's junior sister Qing Yi opposed their relationship and teamed up with her admirer, fellow disciple Cui Ming, to separate the couple.
Pian Pian, a butterfly spirit, coveted Lu Dongbin's pure yang energy.
Meanwhile, Lu Dongbin's classmate Jia Ren plotted to imprison him and seize his assets, resulting in the death separation of the lovers.
Lu Dongbin loved Yin Dai deeply and refused to believe that their love was fleeting.
He risked his life to retrieve a resurrection herb. Then he practiced the Pure Yang Sword Technique, and guarded Yin Dai day and night, hoping to revive her someday.
However, when the evil side of Yin Dai was released by Pian Pian, she joined forces with the butterfly spirit, Cui Ming, and Qing Yi to harm Lu Dongbin.
Due to mistakenly swallowing Yin Dai's inner pearl, Lu Dongbin gained some power, the butterfly spirit was killed.
But it was against the natural order for a human and a demon to fall in love, with the guidance of Zhang Guolao and Han Zhongli...