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.