A thousand-year-old snake that has transformed itself into a human, Madame White Snake (Choe Eun-hui), falls in love with a young pharmacist named Heo-Seon. Although they encounter difficulties, they are wed, and their love for each other does not change. However, Beophaeseonsa (a Zen priest) and Gwaneumbosal (the Buddhist goddess of mercy) order Madame White Snake, who had transformed into human without being granted permission to do so, to return back to the world of the gods before July 7. Grieving, she prepares to say goodbye to her beloved husband. But before she can return to the world of the gods in time, she falls into a trap set by Dae-yun (Choe Sam), who is attracted to her. Because of the trap, she is not able to keep the promised deadline, and ends up risking her life to save her husband.