Hong Ra-On disguises herself as a man and counsels men on dating. Due to a love letter she wrote for a client, she meets Crown Prince Hyomyeong (Park Bo-Gum). Hong Ra-On is unaware that he is the Crown Prince and Hyomyeong 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.