In the 1990s in the south, Xu Xuan's parents passed away, and his uncle Xu Dafa usurped his family's pharmacy and even wanted to sell his younger sister. Driven to a desperate situation, Xu Xuan braved a flash flood to enter the mountains to look for wild ginseng to pay off his debts, and coincidentally met the white python Bai Zhen, who had failed her heavenly tribulation, and stepped in to save her. With Bai Zhen's help, he gained the ability to travel through the mountains, punish the wicked uncle, rescue his sister, and reorganize the pharmacy. Later, Xu Xuan ventured into the mountains again and saved Bai Zhen's younger sister, the green snake Xiao Qing, from a bully. With the help of the white and green two snakes, Xu Xuan's pharmacy flourished day by day, and ultimately he helped Bai Zhen overcome her heavenly tribulation, transforming from a snake into a dragon.