The Brothers Grimm are invited to an audience with the Grande Dame, who expresses her disappointment in their version of Cinderella. She produces a jeweled glass slipper and recounts Cinderella's true story.
During the French Renaissance, ten years after the death of Auguste de Barbarac, his daughter, Danielle, has been forced to become a servant to her stepmother, the Baroness Rodmilla de Ghent, and stepsisters, Marguerite and Jacqueline. One morning, Danielle has an unexpected confrontation with Prince Henry as he is attempting to flee in order to avoid an arranged marriage, at first mistaking him for a thief. Henry gives Danielle some coins to keep their interlude secret. He is eventually caught by the Royal Guard after stopping bandits from robbing Leonardo da Vinci, whom King Francis has invited to the French court.
Danielle, going disguised as a noblewoman, heads to the palace to buy back a family servant, Maurice, who was sold by Rodmilla. Henry witnesses her arguing with the jailer and, impressed by Danielle's passion and intelligence, orders the jailer to release Maurice. When he asks for her name, Danielle gives her mother's name, Countess Nicole de Lancret. King Francis strikes a deal with Henry later that night. He will hold a masquerade ball at which Henry will announce his engagement to the woman of his choosing at midnight, or else marry Princess Gabriella of Spain. Hearing this news, Rodmilla accelerates her efforts at getting Henry to notice Marguerite, while being increasingly neglectful to Jacqueline. Meanwhile, Danielle begins secretly spending time with Henry. After an outing at the library of the Francian monks, a gang of gypsies ambushes them, but they offer to help them when Danielle bids the leader and attempts to carry Henry away. At the gypsy camp, they share their first kiss.
Rodmilla and Marguerite plan to take Nicole's wedding gown and glass slippers for Marguerite to wear at the ball. When Marguerite insults Nicole's memory, Danielle attacks her and chases her. Marguerite retaliates by destroying the copy of Utopia that Auguste had given to Danielle. Jacqueline expresses sympathy for Danielle and criticizing Marguerite for her cruelty.
Queen Marie holds a luncheon with Marguerite and Rodmilla and expresses curiosity about the mysterious girl who has taken Henry's fancies. Rodmilla, recognizing the name of Nicole, deduces that the girl is Danielle and reveals she's engaged.
Danielle cannot bring herself to tell Henry the truth so when he tells her she has changed him as a man, inspiring him to build a university. Rodmilla confronts Danielle about her deception and the whereabouts of the dress and slippers. Danielle strongly refuses to return them and Rodmilla locks her in the pantry. Maurice approaches Gustave in going to the ball to recruit Leonardo who helps Danielle escape and Leonardo, Paulette and Louise help prepare her in Nicole's attire. Danielle arrives determined to tell Henry the truth, but Rodmilla exposes her before she can. Furious at her dishonesty, Henry rejects her. Danielle runs away, leaving a slipper behind. Leonardo reproaches Henry for his callousness towards Danielle and leaves him the slipper.
Henry agrees to marry Gabriella, but realizing that she is miserable as she loves someone else, he calls off the marriage. Maurice and Jacqueline tell Henry that Rodmilla sold Danielle to Pierre Le Pieu. Henry rides off to rescue her, only to find that she has freed herself. Henry apologizes, professes his love for her, and proposes marriage by fitting the slipper onto her foot. Danielle happily accepts.
Rodmilla is summoned before the royal court and confronted for lying to Marie about Danielle; she is stripped of her title and threatened with exile along with Marguerite unless someone speaks for her. Danielle appears and instead asks that Rodmilla be shown the same "courtesy" her stepmother had shown her. Rodmilla and Marguerite are reduced to servants in the palace laundry. Leonardo gifts Danielle and Henry with a portrait of Danielle that hung in the university until the French Revolution centuries later.
The Grande Dame reveals to the Brothers Grimm while her great-great grandparents did live happily ever after, the point is that they lived.
