University student K (Seohyun) is an ordinary young woman, but, one day, she finds herself in her favorite romance novel that is set during historical times. She has now become the minor character Cha Sun-Chaek. She is the daughter of a wealthy noble family and her dream is have a peaceful and normal life. Cha Sun-Chaek, while possessed by K, then spends one night with Yi Beon (TaecYeon), who is the lead male character in the novel. He comes from a royal lineage and is favored by the King. Yi Beon has a cold-blooded personality and is gifted with an attractive appearance and outstanding martial arts skills. He has also experienced a heartbreaking past. Somehow, Yi Beon and Cha Sun-Chaek happen to meet and talk. Yi Beon is consoled by her about his heartbreaking past. They spend the night together. Soon, Cha Sun-Chaek tries to connect Yi Beon to Jo Eun-Ae (Kwon Han-Sol), who is the lead female character in the novel. According to the novel, Yi Beon and Jo Eun-Ae are supposed to fall in love, but, due to the appearance of Cha Sun-Chaek, Jo Eun-Ae's fate has changed. No matter how hard Cha Sun-Chaek tries, Yi Beon’s love always finds its way back to her.
Other people around them include Jung Su-Gyeom (Seo Bum-June) and Do Hwa-Seon (Ji Hye-Won). Jung Su-Gyeom is a young officer from a prestigious family. He is Yi Beon’s only friend. Do Hwa-Seon is an ambitious woman whose life goal is to marry Yi Beon and become a member of the royal family.
