Sure, Falstaff's a knight but the guy doesn't have any money—a major problem, since Falstaff's love of food, booze, and women requires lots of cash. He sends identical love letters to the wives of two rich citizens in hopes that he can hit the jackpot.
Not so fast, Falstaff. The "merry wives" of Windsor aren't about to cheat on their husbands with some scumbag who thinks he can get them into the sack. Mistress Page invites Falstaff to her house, pretend-flirts with him, gets him to hide in a basket of dirty laundry, and then arranges for him to be dumped in a river.
Humiliating Falstaff is so much fun that the wives decide to do it again. This time, they invite him to the house and trick him into dressing up as an old woman, who Master Ford beats to a pulp.
Oh, did we mention that Master Ford has some serious control issues? The guy suspects his wife is cheating on him so he tries to catch her in the act with Falstaff, which just makes him look silly. Twice.
It's not enough for the "merry wives" to humiliate Falstaff by getting him beat up and dumped in a river. During the play's climax, the wives arrange for Falstaff to go into the woods, where a pack of children dressed up as fairies attack him. Did we mention that the entire community of Windsor shows up to see it happen?
After the wives jump out of the bushes and yell "Ah ha!," Falstaff admits the wives got the better of him.
The fun's not over yet. Master and Mistress Page have a daughter named Anne. She strolls in and is all, "Guess what, mom and dad. I just married that boy you both hate!"
All is forgiven, and the Pages decide to go with the flow after learning their daughter got hitched to a guy they can't stand. They throw a wedding feast and even invite Falstaff.