A fifteen-year-old Mia lives in San Francisco and has a normal life for an American teen. But her father dies, and Mia finds out that he was a prince of a European country, and now she is the only heir to the throne. Her grandmother, the Queen arrives to California to tell Mia about her origins and to find out whether she would take the throne. She wants to make Mia a real princess by teaching etiquette and manners. By her sixteenth birthday, girl has to decide whether she goes to Europe to run the country, or stays with her mother in San Francisco, having the ordinary life of an American teenager.