The Eldest Princess Wants a Divorce is a period romance-revenge drama. Princess Jiang Mingzhen of Yong Kingdom, disguised as an ugly orphan to test fiancé He Li'an, helps him become top scholar in three years. But she uncovers his affair with widowed sister-in-law Su Niannian—who plot to steal her wealth and kill her.
Enraged, she turns their wedding into a "divorce feast" to expose them. Harassed in the market, she's saved by Prince Lu Zhao of Zhenbei, who's drawn to her and vows to "steal" her at the feast.
At the feast, He and Su humiliate her, but Lu arrives with troops. Jiang reveals her true identity as princess; the royal family crushes their schemes. Su loses her title, He is stripped of his degree, both jailed.
He escapes to kidnap Jiang, but Lu rescues her, ending his malice. Jiang and Lu marry, while He suffers in prison for his crimes. Blending revenge, love and court intrigue, it traces Jiang's growth from betrayal to happiness.
