At the Garter Inn, Simple is looking for the fat woman of Brainford. She is also known as a wise woman, and he has a question to ask her from Slender. Simple asks to see Falstaff, because he has caught sight of him still in his disguise and thinks that the woman is in Falstaff's room. After Falstaff tells the Host that she has gone, Simple tells Falstaff that Slender wanted to ask the wise woman whether he would marry Anne Page. (Apparently the old woman has a reputation as a fortune-teller.) Falstaff gives him a "wise guy" answer that doesn't tell him anything, and says he heard it from the old woman herself. Satisfied with this, Simple leaves.
Bardolph enters with news that the Germans have stolen the Host's horses, but the Host is loathe to believe the worst of his guests. That is, until Evans enters with the information that the Germans have tricked all the innkeepers of the nearby towns of their horses and their money. Caius confirms that there is no duke at the court who goes by the name that the Germans have supplied. Distressed, the Host calls for a hue and cry to catch the thieves. He exits with Bardolph.
Mistress Quickly enters and says she has come from Mrs. Page and Mrs. Ford. Falstaff is in no mood to listen to her, and says he has suffered enough. She says that the women have suffered too, especially Mrs. Ford, who has been badly beaten by her husband. Quickly presents Falstaff with a letter (presumably from Mrs. Ford or Mrs. Page), and he invites her into his room.
In scene 6, Fenton promises to pay the Host even more money than he has lost if he will cooperate with him. Fenton explains that Anne has been told by her father to slip away from the forest in her disguise as the fairy queen, and go to Eton where she will be immediately be married to Slender. Fenton says that Anne has consented to this plan (which obviously is against her wishes). But Mrs. Page, says Fenton, has other plans. She has arranged for Anne to slip away and be married to Caius, to which plan it appears that Anne has also agreed. Page expects his daughter to be dressed in white in the forest, whereas Mrs. Page expects her to be dressed in green. The color of her clothing is important because that is how the would-be grooms will be able to recognize her. Fenton wants the Host to secure the services of a vicar and to wait at the church, where he intends to bring Anne and marry her.
Act 4, scene 5 concludes the subplot about the horse-stealers. Although it is not really integrated with the main action of the play, it does have some thematic relevance. Virtually everyone in the play tries at some point to deceive someone else, and yet the deceivers eventually discover that they have also been deceived (this will not become fully apparent until the last Act). The deceit of the Host in this subplot contributes to this theme, since earlier he practiced his own form of deceit (on Caius and Evans).
In scene 6, Fenton's speeches in blank verse are the longest verse passages in the play. They serve to inform the audience of the plots that will create some of the humor in the last act.