Elder princess Huaiyu Li dedicates all her efforts to assisting her brother, the young Emperor Huailin Li, in governing the country, but is framed for the murder of Sima and disrupting the order of the court and sentenced to death with a cup of poisonous wine. She survives, but with her appearance changed, and somehow assumes the identity of the fourth daughter of the Imperial Censor, Zhuji Bai. After getting a clear hold of the political situation, Huaiyu Li decides to make use of her new identity to investigate the Sima case. She intentionally gets close to the royal advisor Xuanjin Jiang, who sent her the poisoned wine, but discovers that Xuanjin Jiang is not the person who framed her and decides to work together with him to investigate the case. In the process of investigation, they also destroy the corrupted ways of the court. Xuanjin Jiang puts aside his prejudice of Huaiyu Li and realizes that she is an upright person. They also fall in love with each other.