Dan Bi is a senior high school student applying for the College Scholastic Ability Test. 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. She then falls in love with Lee Do, the young king who is in a difficult situation due to droughts and the spread of an epidemic.

A high school student (Dan Bi) escapes from her time to the Joseon Era, where she has to prove her knowledge to survive.