Dan-Bi is a senior high school student. She has a special ability which allows her to transport to anywhere on rainy days. For her university entrance exam, Dan-Bi can't deal with the pressure and runs off to a playground. Without knowing why, she goes into a puddle and finds herself transported to the Joseon period. There, she meets Lee Do. He is a young King of the Joseon period. Lee Do is in a difficult situation due to droughts and the spread of an epidemic.