Hong Ra On dresses up as a man and gives advice to men on dating. Due to a love letter she wrote for a client, she meets Lee Young, who will become Crown Prince Hyomyeong. Hong Ra On has no idea that he's the Crown Prince, and Lee Young has no idea that Hong Ra On is a woman. The Crown Prince grows interested in Hong Ra On. His eunuchs find out about this and try to get Hong Ra On to become one of them.