小白蛇白夭夭初化人身,对世间的一切都感到懵懂无知,在九奚山修仙的紫宣不懂情却偏偏爱上了小白。历经了生死离别,紫宣转世成药师宫宫上许宣,在桃花节和白夭夭邂逅,历经波折两人终成眷属。但白夭夭为救许宣盗取仙草,触犯天条,病愈的许宣忆起前尘往事,只身救回夭夭。师妹冷凝嫉妒白夭夭,引得蛟龙出世,为祸人间。白夭夭为了自我救赎,被齐霄镇压于雷峰塔下,许宣悲痛欲绝...Zi Xuan is the disciple of the Green Emperor and he specializes in medicine and is cultivating to become a deity. He meets a little white snake, whom he nicknamed Xiao Bai, and kept as a pet. Over the course of time, Xiao Bai gathered enough cultivation to transform into a human, and she eventually grows closer to Zi Xuan and developed a close/intimate relationship with him. While trying to find a herb that would save Zi Xuan's life after he is injured, she accidentally breaks a heavenly seal at the elixir chamber of Mount Jiuxi and releases an ancient beast, the black water dragon from imprisonment to the human world. To save the world, Zi Xuan sacrifices himself and disintegrates, but before he fades, he gives Xiao Bai a proper name: Bai Yaoyao. After Zi Xuan's death, Bai Yaoyao is devastated and decides to retreat from the world. A thousand years pass by and they meet again. Zi Xuan, now reborn as Xu Xian, who is the chief of the Yao Shi Palace (medicine valley), remembers nothing of his and Bai YaoYao's past. However, she remembers everything and she tries to ensure that he lives a peaceful life.