9th century China. Ten-year-old generals daughter Nie Yinniang is abducted by a nun who initiates her into the martial arts, transforming her into an exceptional assassin charged with eliminating cruel and corrupt local governors. One day, having failed in a task, she is sent back by her mistress to the land of her birth, with orders to kill the man to whom she was promised - a cousin who now leads the largest military region in North China. A slave to the orders of her mistress, Nie Yinniang must choose: sacrifice the man she loves or break forever with the sacred way of the righteous assassins.