In 654, during the Tang dynasty, Wu Zetian (then a concubine of Emperor Gaozong) murdered her firstborn daughter (posthumously known as Princess Andingsi) and pushed the blame to Empress Wang.

Zhaoniang and the young princess escape from the capital and venture further north into the desert regions.

Several years later, the princess has grown up and she develops a romantic relationship with Axiena Simu, a young Tujue prince.

She decides to seek vengeance on her mother Wu Zetian, who has seized the Tang throne and currently rules as a female emperor.

As the two princesses resemble each other in appearance, the older one impersonates her younger sister and returns to the palace, where she plots her revenge and schemes to take over her mother's place as the ruler of China.