Mia (Anne Hathaway), a 15-year-old high school student, lives in the United States with her mother, but she is very unconfident and is often laughed at by her classmates. On her 16th birthday, she met her grandmother (Julie Andrews) and found out that this elegant lady was the queen of Genovia, a small European country, and Mia was the princess of this country. At first, Mia was very reluctant, but her attitude eased with the mediation of her mother. In order to smoothly inherit the throne, the queen had to make a series of changes to her granddaughter, which made Mia, who was casual in her daily life, very troubled, and even had conflicts with her good friends. But Mia's identity was revealed, and she suddenly received high attention from the media. Everything that happened suddenly made Mia want to escape everything, but fortunately, in her father's diary, she regained her confidence. Mia became a princess and found the love she wanted.