The legend of the immortal white snake is a tale that dates back to the Tang Dynasty between 618-907, it’s script being set in Qing Dynasty during the reign of the Qianlong Emperor (1733-1735).
It goes like this.:
An accomplished herbalist named Xu Xian and his wife Bai Su Zhen opened a medicine shop in Zhenjiang, which flourished with their hard work and dedication. However, this all changed when a monk named Fahai visited Xu Xian to inform him that his wife Bai Su Zhen was a demon snake rather than a human being. Xu Xian dismissed this unconvinced, so to prove it for himself Fahai gave him a special drink urging him to give it to his wife on the 5th day of the 5th month, when she would be the weakest.
To prove to himself that he was right, he tricked his wife into drinking it, almost as soon as it touched her lips she turned into a huge white snake. In horror, Xu Xian collapsed to the ground, dying from shock. After turning back into her human self, Bai Su Zhen decide to steal a magic herb from the forbidden peaks of the Kun Lun Mountains guarded by Shouxing (also known as the Old Man of the South Pole), to resurrect her husband.
Having got there, she disguised herself as a monk claiming to the deer boy and white crane boy (two of the old man’s disciples) that she’d come to invite the old man to a gathering of the Gods. While they went to give the message, Bai Su Zhen plucked some leaves from the plant, however as she tried to escape the deer boy and white crow boy returned and fought her to take the leaves back. Upon this upheaval, Shouxiang allowed Bai Su Zhen to take the leaves out of sympathy. When she came back, she revived Xu Xian and they lived happily ever after.
The legend of the immortal snakes’ core plot revolves around Daoist search for immortality and the struggles between good and evil or yin and yang.