Act One

Late September 1840. The exterior of Le Divan du Théatre, a street cafe next to the stage door of the Paris Opera. The lights come up on a frozen tableau. A party is in progress, celebrating the opening night of La Favorite, an opera by Donizetti. Mariette, a young girl, is dancing a "matelotte" as the partygoers watch, entranced. The tableau comes to life as Mariette's dance finishes to great applause. Monsieur Albert steps forward and tells the audience how Mariette came to be at the cafe on that particular night ("Prologue").

1829. Petit, the dancing master, is rehearsing the Corps de Ballet. Albert tells how the Duke of Bordeaux chose a young ballerina named Louise to be his lover. When the Duke discovered that Louise was pregnant, he left her destitute. Alone with her child, Louise had to dance in taverns for money. Now homeless and wandering, their road carries them back to Paris. Louise collapses in front of the Le Divan cafe. Albert steps forward to help and is amazed to recognize Louise as the former prima ballerina. The Stagehands, Ballerinas and Petits Rats (children who practice at the Ballet School) pass Louise and Mariette on their way to rehearsal ("Here Comes the Daily Grind").

Monsieur Albert and Guillaume, the cafe owner, continue to wait on Louise. Amélie, a Petit Rat and Guillaume's daughter, runs back to the cafe, having left her dancing shoes. She flirts with Albert's assistant, Francois, and makes quick friends with Mariette, the kind Madame. Silvain offers to take Louise and Mariette in to live with her family.

Antoinette gathers the Petits Rats outside the door to the Ballet School. We meet the various Rats as they prepare for class. Madame Grosnier comes out of the school, and the children play tricks on her, driving her crazy ("Little Rats!"). Petit joins her and the children until they run inside for lessons. As he beings the morning exercises, Petit nags the children, especially Marie, who is late again ("Ballet School").

The Duke comes to the Ballet School and encourages the Rats. Their performance of The Vegetable Ballet is only two days away. The children are very impressed with the Duke and vie for his attention, but the Duke pays special attention to the lovely Katrine, making the other children jealous ("Fruit and Veg Song"). Soon, the day is done ("Go Home Now").

Madame Silvain arrives home with Louise and Mariette. Monsieur Silvain is hard at work making ballet shoes. Spotting Mariette's dainty foot, Silvain remarks that she has a true dancer's foot and compares her to Cinderella. Louise doesn't want her daughter to be a dancer, but Silvain fits Mariette with a ballet shoe. Mariette is in heaven – the lovely shoes make her want to be a dancer more than anything. Alone, Mariette asks her mother about her father, and Louise confides that he was a rich man but not a kind man. As Louise sleeps, Mariette sings to herself ("Here's a Shoe"). She is interrupted by Francois at the door with a note for her mother – Guillaume has offered Louise a job at the cafe. Alone, Mariette asks Francois to tell her about what life is like at the Opera.

The Opera House. La Favorite is in full swing. The ballerinas line up for their entrance. Albert notices the Duke backstage waiting for the young, lovely ballerina, Pauline Duvernay. They are interrupted by Grenville, another of Duvernay's admirers. The men vie for her attention. Duvernay tells Grenville to knock out one of his teeth if he wants to secure an audience with her. Albert invites the Duke to the cafe for a party after the performance. The Duke promises to come – and to bring Pauline Duvernay with him.

Albert explains that his task is to bring all of the characters of the story closer together and to find out if they will live happily ever after or not. He wonders if Mariette will play Cinderella in the upcoming opera ("A Tanto Amor"). The song becomes an aria from La Favorite as we transition to the cafe.

The party is in full swing. The children dance The Vegetable Ballet for the customers. The Duke and Pauline Duvernay enter, followed by Grenville, who is missing a front tooth. The Duke recognizes Louise but is interrupted by Albert before he can speak to her. Encouraged by the guests, Mariette sings ("The Skylark") and dances a "marotte." Everyone is entranced by her fresh, natural talent, and the Duke realizes that Mariette is his daughter. He arranges to pay anonymously for her to attend the Ballet School but says that she must never know that he is her benefactor. Louise turns to Guillaume for advice, lamenting that Mariette ever sang or danced in public. He tells her not to worry and, together, they wish for better times ahead ("My Dear Guillaume").

Two days later. Silvain presents Mariette with a new pair of ballet slippers and tells her that she must keep them a secret from her mother – she is going to the Ballet School! Albert joins in the fun of the surprise, and Mariette, mistaking him for her benefactor, thanks him for his kindness ("Thank You, Thank You, Kind Monsieur").

At the Ballet School, Monsieur Petit and the Petits Rats are gathered around the Duke. The Duke announces that the Petits Rats will perform in Cinderella that coming December. The children, including Mariette, must audition for the Duke so that he may cast them in their roles ("Meeting the Duke").

After school, the Petits Rats meet their Mothers outside of the cafe. Amélie tells Louise that she and Mariette have been cast as rats in Cinderella. Louise is furious and forbids Mariette to participate. Albert tries to reason with her, but it is of no use ("Finale Act I"). Albert takes Mariette and Amélie to the theatre to try to calm them down and shows them the beautiful gaslights that he cares for. Amélie and Mariette marvel at the beautiful costumes in the glow of the gaslights. Mariette slips on a costume and begins to dance. Amélie cautions her not to dance near the gaslight, but Mariette doesn't listen. Her dress bursts into flame as Les Petits Rats materialize from the shadows.

Act Two

Three months later. Albert, having lost his job as lumiére, is unemployed and destitute. He regrets letting Mariette and Amélie play on the stage, unattended ("Prologue").

In the hospital, Louise reads Cinderella to Mariette. There is a visible burn on Mariette's face. Francois comes to visit and learns that Mariette will be home soon. When he leaves, a doctor arrives to help Mariette practice her walking, but she can barely bend her legs. The doctor is replaced by Petit as the hospital becomes the Ballet Studio. The other ballerinas join Mariette as the Opera prepares for Cinderella ("Mariette's Ordeal").

Mariette practices more diligently than any of the other Rats. The Rats tease her, but the Ballerinas notice her talent. Madame Grosnier pays Matiette special attention, bringing her soup and bread to keep up her strength. The Petits Rats become even more jealous of Mariette as Petit and Grosnier spend extra time with her. Mariette is dancing for Albert.

Guillaume drinks as he counts the money from the week. Amélie asks her father if she can help. As they work, Amélie tells him about the situation at the Ballet School – inexplicably, Guillaume explodes in anger and rushes out the door.

Louise sits darning a ballet shoe. Monsieur Silvain is upset – the shoes are of poor quality and will ruin Mariett's feet. The Silvain's children run in. Pierre is convinced that he's just seen Monsieur Albert down the street, but Annette is doubtful because the man looked too old. The Silvain children are jealous that Mariette is receiving private lessons with Petit. The Silvain family leaves, and Guillaume barges in, demanding to know when Louise is coming back to him. Louise asks if she can start working at the cafe again the following Monday, but Guillaume wants more. Obviously in love with Louise, he accuses her of taking the Duke's money again. He tells her that the Duke is paying for Mariette's school. Furious, Louise attacks Guillaume, but his hands close around her neck. Mariette enters and stops in her tracks.

A Parisian back street. Albert sits downstage. A Hurdy Gurdy man plays quietly ("Oh Marie"). Louise appears and asks Albert to come home with her. To his relief, she tells him that Mariette is alright, but Albert still refuses to come back with her.

At the rehearsals for Cinderella, Pauline Duvernay is fed up with the squabbling Rats ("Little Rats – Reprise"). She tells Petit that, unless he can get his Rats under control, she will not participate. The Rats poke fun at Mariette, and she accuses them of being jealous of her. They tell her to go back to where she came from ("Oh No, Mariette"). Mariette runs out in tears. Once she is gone, Alice and Marie devise a plan to get rid of Mariette, once and for all. They will push her into Pauline Duvernay ("Those Who Anger Duvernay").

Duvernay complains about Mariette to the Duke. He defends Mariette, but Duvernay will have none of it. She threatens to quit if things don't improve drastically with the Petits Rats. Duvernay storms out as Louise enters. She asks the Duke to take Albert back as the lumiére at the Opera. When the Duke refuses, Louise accuses him of being a terrible person. Louise wonders why she ever brought Mariette to Paris ("Why Did I Ever Bring Her Here?").

Grosnier and Francois comfort Mariette. She is worried that the other Rats will be cruel to her again. Francois gives Mariette a bonbon – and a kiss – to cheer her up. The Petits Rats and Ballerinas enter; the children are going to put on a show for their parents and the Duke. As the show begins. Marie and Alice accidentally push Amélie into Duvernay instead of Mariette. Duvernay is badly injured, but Amélie insists that she was pushed. Mariette is furious. She knows that the push was meant for her. Guillaume screams that Mariette is just like her mother – she must always be the center of attention. Calling for Albert, Mariette runs out into the street.

Albert is slumped on the street, dead. In his hands, he clasps Mariette's beautiful ballet shoes from Monsieur Silvain. Mariette sings to him, calling him her father ("Albert"). Francois gently takes the shoes from Albert and gives them to Mariette. The rest of the Company arrives. They all mourn Albert. Mariette pledges to dance for him. The Duke recommends that Mariette play Duvernay's part that evening.

The Cinderella Ballet begins. Mariette appears after the performance with her ballet shoes in her hands. The crowd applauds wildly for her. The Duke encourages her to stay and be the new star of the ballet, but Louise tells Mariette that it's time to go. Mariette hands the Duke her ballet shoes and runs into her mother's arms ("Finale Act II"). Mariette and Louise leave together.