When Princess Rosalinda (Lovato) is about to become queen of her country of Costa Luna, the country is overthrown in a coup d'etat by an evil dictator. She is put into the Princess Protection Program, a secret organization funded by royal families that looks after endangered princesses. Rosalinda is taken under the wing of Mason (Verica), an agent in the PPP from rural Louisiana. While there, she meets his daughter, Carter (Gomez), an insecure tomboy who works at the local bait shop. Carter dreams of going to the school dance with her crush, Donny, (Adamson), the school hottie. In becoming a normal teenager, Rosalinda takes up the name Rosie and soon becomes popular at school, which Carter must learn to handle. The two become close friends, with Carter teaching Rosie to act like a normal American girl, and Rosie helping Carter to find her inner princess. At the end Rosie becomes Queen of Costa Luna and Carter and Ed cheer, "Long Live Queen Rosie!" and Rosie walks down the aisle with Carter proud and smiling.