Taeyong is your typical 9 to 5 white collar worker at a local engineering company in Seoul. He is everyone's sweetheart in the office and recently just got engaged to his girl, Yoojung. One day, on his way home, Taeyong accidentally hit a tree and collapsed. 

He wakes up to the era of Goryeo Dynasty, somewhere over a thousand years before he was born. Dumb-founded, frustrated, confused.. Taeyong isn't sure how he ends up at such place. 

Princess Haeeungyong is King Taejo's princess who is rebellious and does not care about the throne. Being born as one of the youngest, she was spoiled as a child and always gets what she wants. She wants freedom, and hates being in the palace. Outside the palace, coincidentally, she meets Servant Taeyong.

She is a princess, and he is a servant who has no name in the royal families. Follow the journey of these two love birds as they experience the big differences between their family classes, fall in love and... stay together.