A story between the dragon king and a young maidservant follows a promise of three lifetimes to wait for a loved one.Liu Ying is Xia Hou Xue's maidservant who accidentally encounters a snake. Liu Ying saves it without realizing that the snake is a thousand-year-old dragon called Yuchi Longyan. To repay her debt, Yuchi Longyan promises Liu Ying to marry but it results in a misunderstanding.