During the Joseon Dynasty, the kingdom was caught in a political storm. Cheo Seon was born as a posthumous child and was separated from his mother right away. When he meets So Hwa, the daughter of a powerful noble, he instantly falls for her. He willingly becomes a eunuch to be close to So Hwa. Upon entering the royal palace, he witnesses King Sung Jong and So Hwa spend their first night together. He becomes So Hwa's devoted protector. As political intrigues unfold among the courtesans and wives in the palace, So Hwa is chosen by the king to be his queen, and Cheo Seon pledges to be her loyal servant. However, So Hwa is ultimately dethroned and leaves the palace in disgrace. Cheo Seon helplessly observes these events and secretly aids So Hwa. But in a cruel twist of fate, he is the one chosen to carry out So Hwa's death sentence by serving her a bowl of poison. After So Hwa dies, he takes care of her son, King Yeon San, as if he were his own.
