Late eighteenth or early nineteenth century.
In the run-down mansion of Don Magnifico, Baron of Montefiascone, his two daughters, Clorinda and Tisbe, try on finery while Cenerentola (Cinderella), his stepdaughter, whose given name is Angelina and who serves as the family maid, sings a forlorn ditty about a king who found a wife among the common folk.
When a beggar appears, the stepsisters want to send him away, but Cenerentola offers him bread and coffee. While he stands by the door, several courtiers arrive to announce that Prince Ramiro will soon pay a visit: he is looking for the most beautiful girl in the land to be his bride. The sisters order Cenerentola to fetch them more jewels. Magnifico, awakened by the commotion, comes to investigate, scolding the girls for interrupting his dream of a donkey that sprouted wings. When he learns of the prince's visit, he exhorts the girls to save the family fortunes by capturing the young man's fancy.
All retire to their rooms, and Prince Ramiro - disguised as his own valet - arrives alone, so as to see the women of the household without their knowing who he is. Cenerentola is startled by the handsome stranger, and each admires the other. Asked who she is, Cenerentola gives a flustered explanation about her mother's death and her own servile position, then excuses herself to respond to her stepsisters' call. When Magnifico enters, Ramiro says the prince will be along shortly.
Magnifico fetches Clorinda and Tisbe, and they greet Dandini - the prince's valet, disguised as the prince himself - playing his role to the hilt as he searches for the fairest in the realm. The sisters fawn over Dandini, who invites them to a ball.
Don Magnifico also prepares to leave, arguing with Cenerentola, who does not want to be left behind. Ramiro notes how badly Cenerentola is treated. His tutor, Alidoro, still dressed as the beggar who came earlier, reads from a census list and asks for the third daughter of the household. Magnifico denies she is still alive.
Once Dandini has left with Magnifico, Alidoro tells Cenerentola she is to accompany him to the ball. Casting off his rags, he identifies himself as a member of the court and assures the girl that heaven will reward her purity of heart.
Dandini, still posing as the prince, escorts the two sisters into the royal country house and offers Magnifico a tour of the wine cellar, hoping to get him drunk. Dandini disentangles himself from the sisters and says he will see them later.
In a drawing room of the palace.
Magnifico is hailed as the prince's new wine counselor. No one, he decrees, shall mix a drop of water with any wine for the next fifteen years. Looking forward to the feast, he and his attendants leave. Dandini reports to the prince with his negative opinion of the two sisters. This confuses Ramiro, who has heard Alidoro speak well of one of Magnifico's daughters.
Clorinda and Tisbe rejoin Dandini; when he offers Ramiro as an escort for one of them, they turn their noses up at a mere groom. Alidoro announces the arrival of an unknown, veiled lady. Ramiro recognizes something in her voice. When she lifts her veil, he and Dandini, as well as the sisters, sense something familiar about her appearance. Their confusion is shared by Magnifico, who comes to announce supper and notices the newcomer's resemblance to Cenerentola. All feel they are in a dream but on the verge of being awakened by some rude shock.
In a room of the palace.
Magnifico stews over this new threat to his daughters' eligibility, telling them not to forget his importance when either of them ascends the throne. He leaves with the girls, whereupon Ramiro wanders in, smitten with the newly arrived guest because of her resemblance to the girl he met that morning. He conceals himself as Dandini arrives with the magnificently attired Cenerentola, courting her. She politely declines, saying she is in love with someone else - his groom. At this the delighted Ramiro steps forth. To test his sincerity, she gives him one of a pair of matching bracelets, saying that if he really cares for her, he will find her. After she leaves, Ramiro, with Alidoro's encouragement, calls his men together, so that the search can begin
Once again the prince's valet, Dandini, faces Magnifico, who still believes he is the prince and insists he decide which daughter to marry. Dandini confesses he is a valet. When Magnifico turns indignant, Dandini orders him out of the palace.
At Magnifico's house, Cenerentola once more in rags, tends the fire and sings her ballad. Magnifico and the sisters return, all in a vile mood, and order Cenerentola to prepare supper. She obeys, as a thunderstorm rages.
Dandini appears at the door, saying the prince's carriage has overturned outside. Cenerentola, bringing a chair for the prince, realizes he is Ramiro; he in turn recognizes her bracelet. Confusion reigns as Magnifico and his daughters smart from their defeat; angered by such meanness, Ramiro threatens them, but Cenerentola asks him to show mercy. Her family still against her, Cenerentola leaves with the prince, while Alidoro gives thanks to heaven for this happy outcome.
In the throne room of Ramiro's palace, Magnifico curries favor with the newly created princess, but she asks only to be acknowledged at last as his daughter. Secure in her happiness, she asks the prince to forgive Magnifico and the two stepsisters; born to misfortune, she has seen her fortunes change. Chastened, her father and stepsisters embrace her as she declares that her days of sitting by the fire are over.