The film is set in a medieval realm ruled by a King and his Queen, who have two daughters, the titular Princess and her younger sister Violet. With the Queen's quiet approval, the Princess was trained in the fighting arts by Linh, the niece of Khai, one of the King's advisors. Since the Queen did not bear any sons, the King had intended to wed the Princess to Julius, the ruthless son of a royal diplomat, who despises the King's peaceful reign because of his belief that a "strong" king should rule with an iron fist. The Princess left him at the altar, and as a result, Julius, his whip-wielding henchwoman Moira, and a band of brutal mercenaries have taken the castle by force, seizing the royal family and their retainers.The Princess is locked in the top of her castle's highest tower to await her forced wedding with Julius. When two mercenaries enter and prepare to rape her, she kills them and sets out to rescue her family. After she slays several mercenaries on her way, Julius and Moira are finally alerted and send their men after her. She evades her pursuers and meets up with Linh, who has escaped the castle's sacking and joins in her fight. While trying to reach the sewers, en route to the dungeons, they are forced to fight Moira, and Linh stays behind to stall her. The Princess frees her family, but they and Linh are quickly captured and brought before Julius. When she continues to resist him, Julius decides to cement his claim to the throne by marrying Violet instead. When the Princess fights back, she is thrown into the castle's nearby lake to drown, while Linh and Violet escape through a secret door.The Princess escapes the fall with her life and sneaks back into the castle, where she reunites with Linh and Violet. The three equip themselves with weapons in a secret storeroom, and the Princess and Linh fight the mercenaries, while Violet frees Khai; however, Violet is soon discovered and captured. Linh is wounded while fighting Julius, but the Princess kills Moira and engages him in single combat. Weakened and on her knees, she bides her time while Julius gloats before preparing to kill her. At the right moment, she wrests Julius' sword away and decapitates him. Finally convinced of his daughter's strength and dedication, the King makes her the heir to the throne and decrees that women of the kingdom are allowed to choose their own way in life. (thanks to Wikipedia)