16-year-old Mia is a common teenager from San Francisco. When her father dies, she discovers he was a prince of one European country, and she is the only heir to the throne. Her grandmother, the Queen arrives in California to tell Mia about her origin and offer her to become a real princess. Before she turned 16 she has to decide whether to go to Europe to rule the country or stay with mother in San Francisco and live a life of an ordinary school student.