Ha Jin is a young woman with a fair amount of worries on her mind. One day, her life complicates even more in an instant as she finds herself transported to a different era, to the body of a Goryeo girl named Hae Su. As Hae Su, she meets several royal princes with different personalities. Amongst them, there are two who become especially important to her: the gentle eighth prince, Wang Uk, and the infamous restless fourth prince, Wang So.
They both tell a story of a prince who is exiled from the palace and who develops a passionate relationship with someone they can't be with. In both stories, the main characters are given a prophecy of either destroying their country or shining the brightest light upon it.