During a total solar eclipse, a 25-year-old 21st-century woman, Go Ha Jin (Lee Ji Eun), is transported back in time, to the Goryeo Dynasty.

She wakes up in the year of 941, in the body of Hae Soo, among the many princes of the ruling Wang family, during the reign of King Taejo.

She initially falls in love with the gentle and warm-hearted 8th Prince Wang Wook (Kang Ha Neul), but later develops a relationship with Wang So (Lee Joon Gi), the fearsome 4th Prince, who hides his face behind a mask and is given the derogatory label of “wolf-dog”.

As the story develops, Hae Soo finds herself unwittingly caught up in the palace politics and the rivalry among the princes, as they fight for the throne.