Così fan tutte

Don Alfonso and his young friends Ferrando and Guglielmo are arguing over the fidelity of women. Alfonso insists that all women are fickle, while Ferrando and Guglielmo refuse to believe that their fiancées, the sisters Fiordiligi and Dorabella, could ever be unfaithful. Don Alfonso wagers that by the end of that very day their fiancées will have betrayed them. He instructs Ferrando and Guglielmo to pretend that they have received orders to go off to war.

Fiordiligi and Dorabella are singing the praises of Guglielmo and Ferrando when Don Alfonso arrives to tell them that their betrothed must immediately depart for the battlefield. The young men arrive and the two couples bid each other a tearful farewell. Despina, the sisters’ maid, is preparing their breakfast when Fiordiligi and Dorabella enter lamenting the departure. She counsels them to amuse themselves while their lovers are away, advice that horrifies them. After the sisters leave, Don Alfonso, who has overheard their conversation, recruits Despina to aid him in his plot, asking her to admit two suitors (the disguised Guglielmo and Ferrando) into the house. Fiordiligi and Dorabella are alarmed to find two strange men in their home, and become ever more alarmed when the two men begin courting them. Don Alfonso pretends the men are old friends of his and begs the sisters to accept them. But Fiordiligi staunchly swears fidelity to her absent Guglielmo.

The sisters are lamenting the departure of their fiancés when the two ‘strangers’ barge in and swallow what seems to be poison. When they collapse, Despina and Don Alfonso go in search of a doctor, leaving Fiordiligi and Dorabella to tend to the apparently dying strangers. A doctor (Despina in disguise) arrives to revive the two afflicted suitors. As they recover, they vow their love to the vexed sisters with even greater passion, while Alfonso and Despina try to hide their amusement.

Fiordiligi and Dorabella are persuaded by Despina that there would be no harm in a bit of innocent flirtation. Dorabella chooses the disguised Guglielmo while Fiordiligi chooses Ferrando.

The suitors serenade the two sisters. Fiordiligi goes off for a stroll with Ferrando while Guglielmo courts Dorabella. To his amazement, Dorabella surrenders rather easily. As they go off together, Ferrando returns with Fiordiligi, who continues to resist him and leaves. When the two young men exchange news of their progress, Ferrando is stricken to learn that his faithless Dorabella has yielded to Guglielmo.

While Don Alfonso and Guglielmo covertly look on, Ferrando makes another attempt to break Fiordiligi’s tenacity. To Guglielmo’s distress, she too finally yields. Don Alfonso has now won his wager. He tries to console the two young men with his motto: ‘così fan tutte’ (‘all women are like that’).

The sisters’ weddings to their two suitors are proceeding when a military chorus in the distance signals the ‘return’ of Ferrando and Guglielmo from battle. The suitors and the notary (again Despina in disguise) hide. A moment later Ferrando and Guglielmo appear in uniform, feigning the cool reception they receive. When they discover the marriage contract and the notary, they swear vengeance on their faithless fianceés and their suitors. Finally, they reveal their ruse and the two pairs of lovers are reconciled. Or are they?