In the sixth year of Tianyou, Zhizong died, and his second daughter, Princess Chu Jiuling (played by Peng Xiaoran), questioned her uncle's regicide and usurpation of the throne. After experiencing a series of sudden changes such as the destruction of his family, Jiuling was determined to find out the secrets of Zezhou, expose the truth about his father's murder, and protect his loved ones. With the help of Zhu Zan (played by Jin Han), the son of Chengguogong, Jiuling insisted on saving the world and saving people, constantly fighting against the harassment and attacks of treacherous officials, and established Jiulingtang, a medical clinic, to treat smallpox and protect the people. At the same time, Zhu Zan, the noble son Ning Yunzhao, his ex-husband Lu Yunqi, and Fang Chengyu, the only son of the Fang family, four people with different identities and complicated relationships, fell into an emotional whirlpool with Jiuling as the core. Who is Jiuling's true son of heaven? The gears of fate are turning slowly.