In a charming story set in 17th-century France, a spirited seventeen-year-old girl named Corinne, played by Barbie, dreams of following in her father D'Artagnan's footsteps and becoming a Musketeer. She lives modestly on a farm with her mother, but her heart is set on adventure, heroism, and proving herself as a brave defender of justice. Through her journey, she is accompanied by her adorable kitten, Miette, who amusingly dreams of becoming a "mus-cat-eer," adding a touch of lightheartedness and whimsy to the narrative.
When Corinne and her feline companion finally arrive in Paris, she quickly discovers that her dreams are not easily realized. Despite her enthusiasm, she faces ridicule from the townspeople, especially from Prince Louis's cousin and advisor, Philippe. During this chaotic first encounter, her letter of introduction to the renowned musketeers is stolen by Brutus, a mischievous dog owned by Philippe, and runs off to the royal castle. Corinne manages to retrieve her letter, but Brutus damages it in the process. She then has a brief but important conversation with Monsieur Treville, the head of the musketeers, who gently tells her that she is not yet ready for such a dangerous and demanding role.
Things take a turn when Brutus, in a playful yet problematic manner, chases Miette toward the castle, causing a commotion involving three palace maids. Fortunately, Madame de Bosse, played by [Merrilyn Gann], notices Corinne’s determination and hires her as a palace maid, giving her a chance to stay close to the heart of Parisian life. Despite this rocky start, Corinne’s kindness and perseverance earn her the friendship of other young maids: Viveca (played by [Kira Tozer]), Aramina (played by [Willow Johnson]), and Renee (played by [Nicole Oliver]). These new friends, initially wary, come to appreciate Corinne, forgiving her past mishaps and bonding over their shared dreams of becoming musketeers.
The story progresses as Corinne encounters Prince Louis for the first time during her duties. An amusing accident occurs when a chandelier nearly falls on him, but he narrowly escapes. In the chaos, Corinne, Viveca, Aramina, and Renee demonstrate surprising bravery and skill as they fend off falling debris, uncovering a mysterious gemstone attached to a cut rope near the chandelier. This find sparks their curiosity about the possibility of their involvement in a larger adventure because each of them reveals that they also dreams of becoming musketeers, just like Corinne.
Their secret aspirations are overheard by Helen, an old maid who guides them through a concealed passageway to a forgotten musketeers' training room. Recognizing their potential, Helen agrees to train the girls, transforming their courage into real skills. As they learn and grow, Corinne’s bond with Prince Louis deepens after she heroically rescues him from a hot-air balloon accident. The prince, grateful and smitten, thanks her and hints at his feelings, which ignites her own growing affection for him. During this adventure, Corinne notices that the rope attached to the balloon has also been cut, echoing the earlier suspicion linked to the gemstone, hinting at treachery brewing within the castle.
Prince Louis confesses that girls cannot be musketeers, but Corinne defies his expectations, storming off with her friends to uncover the truth. Helen warns them about potential enemies lurking around, which ultimately sets the stage for a daring plot. Miette, with the help of Corinne’s trusted horse, Alexander, sneaks into the castle to join their training, and soon, the girls complete their rigorous preparation.
Their opportunity to act arises when they uncover a scheme to assassinate Prince Louis at a masquerade ball. Men led by a mysterious figure known as Regent are secretly smuggling weapons into the event to weaken the prince’s defenses and place his treacherous cousin Philippe on the throne. When the girls attempt to warn Monsieur Treville and the musketeers, they are dismissed and forbidden from entering the castle’s festivities. Undeterred, they disguise themselves and infiltrate the ball, where Louis, unaware of their true identities, chooses to dance with Corinne.
The evening turns chaotic as the villains strike, capturing Treville and the musketeers, attacking the girls, and forcing the prince into a perilous chase to the rooftop. Despite the danger, Corinne’s quick thinking and bravery help her rescue Prince Louis at the last moment, leading to the capture of Philippe, Regent, Brutus, and their henchmen. The villains are defeated, and justice is served.
In the aftermath, Corinne and her friends reveal their identities, removing their disguises. Louis, impressed by their courage, officially names them royal musketeers on his coronation day. Madam de Bosse is reassigned to a more modest role as a maid, replacing the wicked Madame de Bosse. Corinne’s mother beams with pride, seeing her daughter achieve her lifelong dream. Prince Louis then offers to take Corinne on another balloon ride, but before she can accept, Monsieur Treville informs them of a new threat against the kingdom. Without hesitation, Corinne and her friends mount their horses, shouting the rallying cry "All for one, and one for all!", and ride off into the sunset, eager to continue their adventures and protect their kingdom from any danger that may come next.
