Don Pasquale, the comic opera of the bel canto genius Gaetano Donizetti, tells a story of an elderly bachelor, who is befooled by his doctor, doctor’s "sister" Norina – a young and beautiful widow, and the bachelor’s lovesick nephew Ernesto who marries the widow in the end. In the tradition of opera buffa, the opera makes reference to the stock characters of the commedia dell’arte: Pasquale is recognizable as blustery Pantalone, Ernesto as the lovesick Pierrot, Malatesta as the scheming Scapino, and Norina as a wily Columbina.
Don Pasquale is a rich old man, whose nephew, Ernesto, would become his heir, but only if he marries his uncle’s chosen bride. But Ernesto loves Norina, a young, very attractive and energetic widow who has no money to speak of. Ernesto refuses to submit to the will of his uncle, and the angry Pasquale decides to exclude him from his inheritance and get married, himself. Dr Malatesta, a friend of Pasquale, but an even closer friend of Ernesto and Norina, devises a plot to help the young couple. He offers Pasquale his sister, Sofronia, as a bride, exaggerating her virtues. Pasquale gladly agrees and immediately drives Ernesto out of his home. Meanwhile, Malatesta uncovers his plan to Norina. She will impersonate Sofronia, marry Pasquale in a mock wedding, and then – drive the old man to desperation.
The despondent Ernesto, who knows nothing of Malatesta's plan, seeks to take refuge in far-flung lands. Malatesta and Sofronia (in actual fact, Norina) arrive, and she instantly enchants Pasquale. The impassioned old man signs a marriage contract, gifting half his property to his new wife, but the contract has been approved by a fake notary. Sofronia, who up until this moment has been timid, silent, and submissive, and in keeping with her arrangement with Malatesta, instantly begins to behave in an arrogant, flirtatious manner and, much to Pasquale’s horror, begins spending his money with abandon.
Sofronia becomes even more temperamental, even giving Pasquale a slap, makes him think that she has a lover. Pasquale, now in complete desperation, begs help from Malatesta, who reveals everything to Ernesto. Ernesto will have to pretend to be Sofronia's lover, at the same time being careful not to allow Pasquale to recognise him. That evening, in the garden of the Pasquale’s villa, Ernesto serenades Sofronia, both declaring their love for each other with a duet. The despairing Pasquale announces to Sofronia that he will drive her out of his house and will allow Ernesto to marry Norina. At that moment, it is revealed to him that the marriage was a farce and a scheme, Pasquale, overjoyed that he has nothing more to do with the devilish Sofronia, forgives everyone and gives his consent to Ernesto and Norina's marriage.