Barbie stars as Corinne, a country girl who dreams of being a Musketeer, protectors of the French royal family, just like her father, D’Artagnan. Now seventeen, Corinne asks her mother to let her go to Paris to become one. Though worried about the dangers, her mother supports her and gives Corinne her blessing, as well as a letter to Monsieur Treville, the captain of the Musketeers and an old friend of her father’s.

The next day before leaving, Corinne’s mother reminds her about what her father use to say: “True courage is pursuing your dream, even when everyone else says it’s impossible.” Hugging her mother goodbye, Corinne sets off for Paris with her kitten, Miette, and Alexander, D’Artagnan’s old horse.

Arriving in Paris, Corinne watches four Musketeers displaying their skills. She tells them about becoming a Musketeer herself and asks them where to find Treville. They tease her as a mean dog, Brutus, knocks her over and steals her letter. Attempting to get it back, Corinne and Miette chase him into the Musketeer headquarters, where Treville is talking to Philippe, the kingdom’s regent and Brutus’ owner. When hearing why she is there, Philippe scoffs at Corinne’s dream to be a Musketeer, saying girls don’t possess the proper skills. However, Treville kindly invites her inside…