The action takes place in Rome, in the house of Lattanzio

ACT I

As the servants at Cherubino's chateau prepare to celebrate the young man's first military commission and his 17th birthday. Nina confesses to Cherubino's tutor Jacoppo (known as the Philosopher) that she has loved his pupil since childhood, even though he now ignores her. The Duke, the Baron and the Count have learned that Cherubino has invited l'Ensoleillad - the celebrated première danseuse of the Teatro Real, Madrid - to come and dance that evening. As the three jealous men ridicule the handsome, dashing Cherubino, he declares his happiness because l'Ensoleillad has accepted. While peasants dance and entertain, the guests watch the festivities on the terrace, and Cherubino tells the entranced Countess that he has left a letter for her in the hollow of an old willow tree. The Baroness too is taken with the boy. Finding his pupil melancholy and downcast, the Philosopher asks why, and the young man confesses that he cannot look at a woman without becoming sick with love; the elder tells him this is only natural. The Count has intercepted the letter from Cherubino to his wife and, in a fury, wants to challenge him to a duel; but the innocent Nina pretends the verses were meant for her and proves it by reciting the madrigal by heart. Although the Count is satisfied, the Countess is irked to learn that Cherubino loves Nina. The Philosopher is delighted to learn that his pupil loves the girl he himself has chosen for him. Cherubino excitedly proclaims that he loves a ravishing creature - not Nina, but l'Ensoleillad, who arrives with pomp and ceremony.

ACT II

In the courtyard of the inn, travellers are trying to get rooms for the fiesta. When the Baroness and Countess are shown to their small quarters, they pronounce them unworthy of their station, but the Innkeeper reveals that the best ones are reserved for I'Ensoleillad, the favourite of the King. Some officers, with their girlfriends (Manolas), celebrate Cherubino as their new companion in the regiment and, despite his dashing uniform and plucky manner, are surprised at his diminutive stature. When Cherubino makes a pass at Ricardo's mistress, the outraged captain challenges him to a duel. A masked woman arrives, and Cherubino brashly embraces her and gives her a rough kiss -- but he apologises when she is revealed to be I'Ensoleillad. The Philosopher pleads with Ricardo to excuse Cherubino because of his youth and inexperience. Ricardo calls off the duel; 1'Ensoleillad - who had fainted in the fracas -- recovers, rebukes the men, offers a toast to love, and launches the fiesta by dancing. The Philosopher warns Cherubino to be on guard against the dangers of leading such an amorous life, but the young man, longing only to see l'Ensoleillad appear on her balcony on such a beautiful evening, sends the exasperated tutor away. Cherubino finally catches sight of the dancer and sings to her. Delighted, she comes down to him, and the two lovers, lost in their blissful private world, vanish into the nearby woods. The Baron, the Count and the Duke decide to thwart Cherubino's attentions to I'Ensoleillad because of the King, but the returning lovers lead them on a merry chase. So that 1'Ensoleillad can return to her room without being caught, Cherubino draws the men into the woods. Quickly returning, he finds a ladder, climbs it and embraces the dancer through the bars of her balcony. The duped men burst on the scene, and Cherubino has just enough time to leap down and mockingly throw the ladder to the ground, making it impossible for them to know at which of the three ladies' adjacent windows it stood. The love tokens Cherubino has been given - a bouquet from the Baroness, a ribbon from the Countess, and a garter from I'Ensoleillad - add to the confusion. Cherubino parries with the outraged men before the police arrive to arrest the noblemen for inciting a riot, and the women faint.

ACT III

The next morning in the inn's courtyard, Cherubino, preparing for three duels, draws up his will. The Baroness and the Countess demand to know whom he was serenading the previous night. As he admits it was 1'Ensoleillad, their husbands return and heap reproaches on Cherubino. The women assure their husbands it was not they whom Cherubino visited but l'Ensoleillad, and so a duel is out of the question. The Duke delivers a royal message summoning the dancer back to court, and she leaves still extolling the wonder of a single fleeting night of love. Cherubino tries to detain her, but, left alone with the Philosopher, he gives vent to his disillusionment and curses love. His tutor advises him to wait for true love with 'a woman who is kind and understanding, one who will console you in adversity.' Just then Nina comes to take leave of Cherubino before retiring to a convent because her love is unrequited. As the young man realises that he is the cause of her sorrow, he begs forgiveness, and Nina is moved by his sincerity. As the two declare eternal love, the Philosopher orders Cherubino to be rid of the Countess's ribbon sticking out of his contrite pupil's coat. Cherubino does so and rushes into the arms of his forgiving Nina.