In the fictional dynasty set in the Joseon Dynasty, a witch in Seongsu Hall was hunted down for witnessing a palace conspiracy, but was saved by Shin (played by Yang Mi-kyung), the wife of the Hongmungwan Supervisor. The witch saw that the girl in Shin's belly was the "Moon of Joseon", noble and glorious, but as long as she approached the "Yang of Joseon", she would encounter a disaster of extermination. In order to repay Shin's kindness, the witch entrusted her friend Zhang Luying (played by Jeon Mi-sun), who was also a witch, to protect the child before she died. Shin gave birth to a daughter and named her Yeon-woo. Thirteen years later, Yeon-woo (played by Han Ga-in) met the crown prince Lee Hwon (played by Kim Soo-hyun) by chance, and Lee Hwon fell in love with Yeon-woo at first sight. Lee Hwon's half-brother, Yang Myeong-gun (played by Jung Il-woo), whom he admired and relied on, also deeply loved Yeon-woo, and his brother's feelings for Yeon-woo made him feel painful. At this time, a conspiracy in the harem completely changed the fate of the three people. The witch's prophecy came true step by step. The love and hatred between the two "moons" and the two "suns" began in the deep palace of North Korea... Adapted from the novel of the same name by Korean writer Jung Eun-que, it set the first place in South Korea's ratings that year.