Fifteenth century London. The curtain rises on the Garter Inn, favorite tavern of Sir John Falstaff, a glutton, drunkard, dreamer, and impoverished knight. Dr Caius, a local quack doctor, storms in and accuses Falstaff of breaking into his house. Falstaff causally confesses. Now Dr Caius turns to Falstaff’s sidekicks Bardolfo and Pistola, claiming they got him drunk and picked his pockets. Pistola and Bardolfo answer Caius with insults. Tempers start to rise, but Falstaff sends the doctor away before anyone gets hurt.
With the doctor gone, Falstaff reproaches Bardolfo and Pistola. Not only are they clumsy thieves, they’re expensive friends-Falstaff can’t afford to buy their food and drink anymore. Luckily, he has a plan to put some money in their pockets and food in their bellies. Falstaff’s eye has fallen on two of the town’s matrons, Alice Ford and Meg. They’re both good natured, beautiful, and well off-but most importantly, they control their husbands’ money. Falstaff plans to seduce them both, and then live off their generosity. He asks his cronies to take love letters to the two women, but they refuse to compromise their honor. Falstaff ridicules the idea of honor, calling it stupid, pretentious, and useless to thieves and beggars like his friends. He ends his tirade by chasing Bardolfo and Pistola out with a broomstick.
Scene 2: In a town garden Meg, Alice, Alice’s daughter Nannetta and their friend Dame Quickly meet to gossip. Meg and Alice have both received love letters from Falstaff; in fact, the letters are completely identical except for the names. Insulted and amazed by the knight’s nerve, the merry wives decide to repay his compliment with a trick. They retire into the distance to plot their revenge.
Enter Alice’s husband, Ford, Nannetta’s boyfriend, Fenton, and Dr. Caius. They are followed by Falstaff’s former comrades Pistola and Bardolfo. Bardolfo and Pistola tell Ford that Falstaff plans to seduce Alice. Ford, a naturally jealous and suspicious man, vows to protect his home from the lusty knight. The young sweethearts Fenton and Nannetta spot each other. While the grownups are busy plotting, they steal away to kiss and swear their love to each other.
Separating reluctantly from Fenton, Nannetta rejoins the women, who have already hit upon a plan. They’ll flatter Falstaff, sweeten him up, make him expect total success-then punish him.
The men have a plan too: Bardolfo will introduce Ford to Falstaff under a false name, and Ford will take it from there. Bubbling with excitement about the fun to come, everyone splits up to put their different plans into effect.
Bardolfo and Pistola return to the Inn and beg Falstaff’s forgiveness. Falstaff magnanimously accepts their apology. Dame Quickly arrives, bearing messages from both of Falstaff’s new "conquests": Alice asks him to visit when her husband is away, but Meg says her husband is rarely absent. Quickly marvels at the knight’s seductive powers before leaving him to gloat over his success.
Now Ford enters disguised as a rich merchant. He explains that he is deeply in love with Alice. He has tried to woo her, but she is faithful to her husband. Ford begs Falstaff to use his superior charm and noble title to win Alice; he hopes that once she’s lost her virtue, she’ll let Ford seduce her. But much to Ford’s surprise, Falstaff says he’s already meeting with Alice that very afternoon-and will cuckold her husband then. Falstaff prances out, leaving Ford fuming with rage and jealousy.
Back at Ford’s house, the merry wives are preparing for Falstaff’s visit. They are interrupted when Nannetta runs in crying: her father has promised her hand in marriage to old Dr. Caius. The women comfort Nannetta, promising they’ll never let her marry the doctor. Everyone but Alice hides before Falstaff enters.
Falstaff swears his love to Alice, flattering her and promising her jewelry, fine clothes, even a noble title. Alice coquettishly accuses him of loving Meg. Falstaff protests that he can’t stand Meg’s face. He grabs Alice and is about to kiss her when Quickly enters in a pretended panic. She warns them that Meg is coming. Alice hides Falstaff behind a screen; so far, everything is going according to plan. But Meg rushes in genuinely frightened; Ford is on his way home, cursing and vowing to kill Falstaff.
Ford arrives in a towering rage, accompanied by Dr. Caius, Fenton, Bardolfo and Pistola. Together they search the entire house for Falstaff. Meg and Alice quickly hide Falstaff in a large laundry basket and cover him with clothes. In the midst of the confusion Fenton and Nannetta sneak behind the screen to steal a few kisses. Ford’s mad hunt for Falstaff finally leads him to the screen. Convinced Falstaff is hiding behind it, Ford whisks the screen away to reveal-- Fenton and Nannetta kissing! The furious Ford forbids the lovers to see each other. Fenton leaves, Nannetta rushes out in tears-and Bardolfo and Pistola shout that Falstaff is on the stairs. The men rush out just long enough for the women to dump the basket where Falstaff is hiding out the window. Falstaff lands in the river outside with a huge splash, and everyone erupts into laughter.
Falstaff sits alone at the Garter Inn, drenched to the bone and brooding over his humiliation. Dame Quickly appears and tries to convince him that Alice actually loves him. Falstaff refuses to believe her at first, but in the end his ego gets the better of him. He agrees to meet Alice at midnight under Herne’s Oak. Quickly explains that the place is haunted by a ghost called the Black Huntsman. They retire inside the Inn to discuss the ghost’s legend.
Nannetta, Alice, and Ford, who have been eavesdropping, come out of hiding to plan their next step. They will disguise themselves as fairies and elves, terrify Falstaff and then force him to admit he’s a knave. The women hurry off to get ready, but Quickly lingers long enough to overhear Ford promising to marry Caius and Nannetta that very night.
At Herne’s Oak, the conspirators finish their preparations. Quickly draws Fenton aside and, without an explanation, dresses him in a different robe. The group scatters before Falstaff appears, ridiculously costumed and primed to seduce his lady love.
When Alice joins him, Falstaff passionately declares his love for her. Meg arrives in the nick of time and tells them that the fairies are coming. Falstaff, who’s heard that anyone who sees the fairies will die, lies face down on the ground and hides his eyes.
Nannetta, dressed as the Fairy Queen, enters surrounded by other conspirators disguised as supernatural creatures. After a short song they "discover" Falstaff. They pinch, prod, and poke the poor knight, hurling the worst insults at him and demanding that he confess all his faults. Falstaff endures their abuse and admits his guilt, but the longer they torture him, the angrier he becomes. Finally unable to take any more, Falstaff opens his eyes and recognizes Bardolfo. The trick is revealed. Falstaff finally realizes he’s made a fool of himself.
Now Ford steps forward to suggest a wedding; he will marry Nannetta and D.r Caius. Alice announces that another couple wants to join the nuptials, and they agree to make it a double wedding. Ford marries the couples, who are still disguised. But when the couples unmask themselves, Ford gets a huge surprise-he’s married Dr. Caius to Bardolfo, and Nannetta to Fenton! Ford accepts his mistake with good grace, and Falstaff calls for a chorus to finish the opera:
"We are all fools!
And every man
Laughs at the others’ folly.