The movie begins with Princesses Isla (Barbie) and Rosella living in the kingdom of Gardania, which is preparing for the annual "Fashion Fairytale" event. Isla, more into books and royal duties, and Rosella, who loves fashion and parties, are very different but are sisters. A magical mishap causes them to switch bodies, leading to comedic and educational situations as each navigates the other's life.

[Scene: Barbie's fashion studio. Barbie is working on a new design while Taffy looks on.]

The night of the fashion show arrives, and Barbie's nerves are on edge. With the help of her friends, she manages to overcome her jitters and showcase her exquisite designs on the runway. The audience is wowed by her creations, and the judges are impressed by her talent and originality.