ACT I
Sir John Falstaff, the portly rascal of Windsor, sits at the inn with his cohorts Bardolfo and Pistola. When Dr. Caius enters to accuse the three of robbing him, Falstaff dismisses the charges with mock solemnity. He then upbraids his friends for being unable to pay the bill. Seeking to better his fortunes, Falstaff plans to woo wealthy matrons Alice Ford and Meg Page. He produces love letters to both, but his henchmen claim their ethics prevent them from delivering the notes. Falstaff gives them to a page boy instead and lectures his cronies on honor, chasing them from the inn. In her garden, Alice and her daughter, Nannetta, talk to Meg Page and Mistress Quickly, discovering that Falstaff has sent identical letters. Outraged, they resolve to punish him, then withdraw as Ford arrives with Caius, Fenton, Bardolfo and Pistola, all warning him about Falstaff's designs. Briefly alone, Nannetta and her young lover Fenton steal kisses until the women return, plotting to send Quickly to Falstaff to arrange a rendezvous with Alice. Nannetta and Fenton are interrupted by Ford, who also plans to visit Falstaff. As the women reappear, all pledge to take the fat knight down a peg or two.
ACT II
At the inn, Falstaff accepts Bardolfo and Pistola's feigned penitence for their mutiny. Soon Quickly appears, to assure the knight that both Alice and Meg return his ardor. Arranging a meeting with Alice, Falstaff rewards Quickly with a pittance, and then preens. The next visitor is Ford, disguised as "Master Brook" and pretending an unrequited passion for Alice. Employed to break down the lady's virtue, Falstaff boasts that he already has set up a tryst and steps out to prepare himself. Ford, unable to believe his ears, vows to avenge his honor. Regaining his composure when Falstaff returns, he leaves arm in arm with the fat knight. In Ford's house, Quickly tells Alice and Meg about her visit with the knight at the inn. Nannetta does not share in the fun: her father has promised her to much older Dr. Caius. The women reassure her the marriage won’t take place before they all hide, except for Alice, who sits strumming a lute as her fat suitor arrives. Recalling his younger days as a slender page, he is cut short when Quickly announces Meg's approach. Falstaff leaps behind a screen, and Meg reports that Ford is on his way over in a fury. While Ford and his men search the house, Falstaff takes refuge amid the dirty linen in a laundry basket. Slipping behind a screen, Nannetta and Fenton attract attention with the sound of their kissing. While Meg and Quickly muffle Falstaff's cries for air, Ford knocks over the screen and pauses briefly to berate the lovers as the chase continues. Alice orders servants to heave the basket into the Thames, then leads her husband to the window to see Falstaff dumped into the muddy river.
ACT III
Back at the inn, Falstaff bemoans his misadventure while downing a mug of wine. His reflections are halted by Quickly, who insists that Alice still loves him and proves it with a note appointing a midnight rendezvous in the park. Alice, Ford, Meg, Caius and Fenton sneak in as Falstaff enters the inn with Quickly, who tells him the gory tale of the Black Huntsman's ghost, often seen in the area at midnight. Alice and the others take up the story, plotting to frighten Falstaff by dressing up as wood sprites. In the moonlit forest, Fenton sings of love and receives a monk's costume for the masquerade; Nannetta is queen of the fairies, Meg a nymph and Quickly a witch. Everyone hides as Falstaff lumbers in, dressed as a huntsman and wearing antlers. Scarcely has he greeted Alice than Meg warns of approaching demons. As the knight cowers, Nannetta calls the forest creatures to their revels. They torment Falstaff until he begs for mercy. When the conspirators unmask, Sir John takes it like a sport. Ford betroths Caius to the queen of the fairies (now Bardolfo in disguise) and unwittingly blesses Nannetta and Fenton. Ford too has been duped, but he agrees to forgive, and Falstaff leads the company in declaring the world is but a jest.
-- freely adapted from Opera News