In 276, Prince Qin Cheng became a disciple of Yan Yuan and followed him to the Western Regions.
In 278, the prince mistakenly entered the Western Forbidden City and was invaded by evil spirits. Yan Yuan exhausted all his magic power in order to seal away the resentful spirit and rescue the prince. And Yan Yuan was taken away by the prince who could not completely get rid of the resentful spirit. This is the beginning of the story...
Intention: love