To protect herself and her family, 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 Hyo Myung. Ra On is unaware that he is the Crown Prince, and Hyo Myung is unaware that Ra On is a woman. Soon after Ra On is forced to become a eunuch by loan sharks, and the Crown Prince and Ra On become interested in each other. As Ra On tries to survive the palace and the Crown Prince navigates his journey to become king, will their love prosper?