A love story between a couple in their early thirties. It’s the story of two people who live in the same era but in different worlds. Oh Yun Joo (Han Hyo Joo) is a surgeon whose father is a famous comic book creator. One day, her father goes missing and she rushes to his workshop to look for him, and instead finds a strange man, Kang Chul (Lee Jong Suk) bathed in blood. She is kidnapped by him and taken to a different dimension.
The series will be simulcast in China. The story set up in the early of Goryeo regime. Hae Soo (IU), a 25 year old girl from modern era got transported back to Goryeo dynasty and got trapped in the conflicts and struggles between princes of Wang’s House. There, she falls in love with Wang So (Lee Joon Ki) who makes other people tremble with fear.
Eun Ha Won (Park So Dam) is a high school student who dreams to be a veterinarian, but needs money for her education. She ends up living in a mansion, Sky House, with three third-generation chaebol cousins under same conditions. Kang Hyun Min (Ahn Jae Hyun) is a playboy plutocrat who does whatever he wants while Kang Ji Woon (Jung Il Woo) is soft hearted but lonely and wild-child rebel who rises in status to a member of the royal family in the Sky House.
Hong Ra On (Kim Yoo Jung), disguises herself as a man and counsels men on dating. Due to a love letter she wrote for a client, she meets Lee Yeong—future Crown Prince Hyomyeong (Park Bo Gum). Hong Ra On is unaware that he is the Crown Prince and Lee Yeong is unaware that Hong Ra On is a woman. The Crown Prince becomes interested in Hong Ra On. His eunuchs become aware of this and attempt to get Hong Ra On to become one of them.