The worlds of royalty and roughing-it collide when the lovely Rosalinda (Demi Lovato) enters the Princess Protection Program and moves in with her new "cousin" Carter (Selena Gomez), a total tomboy. In an unexpected role reversal, "Rosie" learns how to act like an everyday girl and Carter finds her own inner princess. Once they discover what they have in common, they prove that best friends really are forever!