Leonato, Governor of Messina, has just gotten word that he’s to be visited by his great friend Don Pedro of Arragon, who’s on his way back from battle. Beatrice, Leonato’s niece, asks the messenger whether Benedick is returning. We learn that Beatrice and Benedick have been engaged in a war of wits for as long as they’ve known each other, and she seems to be full of scorn for the dude.
Don Pedro, Benedick, Claudio, and Don Pedro’s illegitimate brother, Don John, arrive. Benedick and Beatrice exchange some barbs, and the sum of their interaction is that they both hate love and will never get married. (Unless they fall in love with each other and get married. Ahem.) After all the welcoming, Claudio pulls Benedick aside and reveals that he’s fallen for Leonato’s daughter, Hero. Benedick is full of jokes, and thinks marriage and women are bad news, especially the two combined.
Benedick reveals Claudio’s love to Don Pedro, who’s more sympathetic. Left alone, Claudio confirms to Don Pedro that he’d like to have Hero for his bride. Don Pedro is hyped about the idea, and says that tonight at the scheduled masquerade ball, he’ll pretend to be Claudio and woo Hero on Claudio’s behalf. He’s certain he’ll be able to secure a marriage for Claudio and Hero.
Meanwhile, news of the secret conversation is traveling fast around Leonato’s house. Leonato’s brother, Antonio, has a servant who heard some of the conversation between Don Pedro and Claudio. The servant misunderstood or misheard some of it though, so Antonio’s report to Leonato is that Don Pedro intends to woo Hero for himself. Leonato goes off to prepare his daughter, Hero, for what he assumes will be a proposal of marriage from Don Pedro.
The scene moves to Don John. He’s a jerk, and he likes being a jerk. Don John’s attendant, Borachio, enters with a newsy opportunity for Don John to practice some villainy while he’s at Leonato’s house. Borachio properly heard that Don Pedro plans to woo Hero on Claudio’s behalf. The men all agree that this has great potential for their evil attentions, so they’re off to flirt with some ideas for a while.
Leonato, Hero, Beatrice, and company are getting ready for the masquerade ball after dinner. Talk turns to how Beatrice will never find a man that she likes. Beatrice teases that she’s happy to be a bachelor (a gender neutral term in Shakespeare's day) for life, and even into death. Meanwhile, Hero is reminded that her father instructed her on how to return Don Pedro’s affections, and we learn that Hero is generally an obedient girl.
As the men enter in their masks, everyone pairs off with partners. Don Pedro woos Hero privately. Meanwhile, Beatrice rails about Benedick to her disguised partner (who happens to be Benedick). Don John and his crew are still up to villainy, and they corner Claudio, pretending to think he’s Benedick. They suggest that Don Pedro has wooed Hero for himself. Hearing this news, Claudio declares that he should never have trusted the affairs of love to anyone else. Like a wet towel, he says goodbye to his love for Hero.
The first part of Don John’s dastardly plan is foiled when Don Pedro announces that Hero and Claudio can now get together, as he’s done his job and wooed Hero on Claudio’s behalf. He’s explained all of this to Benedick, but Benedick is too busy being hurt by Beatrice’s mean words to appreciate that Disaster Part 1 has been averted.
As Beatrice approaches with Leonato, Hero, and Claudio, Benedick runs away to avoid further criticism from the lady. Claudio enters, sulking, and he’s immediately transformed from being a taciturn emo kid into a joyous puppy when he hears the good news: Don Pedro did exactly as he promised, and a marriage is being set up between Hero and Claudio. Claudio finds out that he won’t be able to marry Hero for a week, and now everyone has to figure out how to have fun during a week with no wedding and no weird courting conflicts. The answer: create weird courting conflicts. Don Pedro decides he’s going to hatch a plan to get Benedick and Beatrice together, which should be entertaining (or a disaster).
Back to the scheming Don John. Though he couldn’t destroy Hero and Claudio’s courtship, he’s sure he can destroy their wedding. Borachio suggests that Don John convince Claudio and Don Pedro to stand in the orchard outside Hero’s window on the night before the wedding. There, Borachio will be making love-talk with Hero’s servant, Margaret, who he’ll have dressed in Hero’s clothes. From far off, the men will think the girl engaged in inappropriate window activity is Hero, and they’ll write Hero off as disloyal.
Later, Benedick is in the orchard, lamenting that one more brave soldier has fallen to the petticoats of love. Benedick notes that Claudio is changed from being a brave, straight-speaking soldier into a milquetoast (pronounced like "milk-toast," and basically means what it sounds like: a piece of bread that has gotten all soggy), concerned with romantic music, fashion, and poetry. Benedick thinks he’ll never undergo such a ridiculous transformation.
Benedick hides when Don Pedro, Claudio, and Leonato approach. They see him hide, so they put their plan (to coerce him into loving Beatrice) into action. They launch into a loud, supposedly secret conversation about how Beatrice is tearing her hair out over her love for Benedick. They say Beatrice can’t make her love known because she’s certain that Benedick will scorn and mock her. They all leave. Benedick jumps out of the shrubbery, declaring that he can love Beatrice, and he’ll prove it. Beatrice has been sent out to invite Benedick to dinner, and Benedick dotes on her, already exhibiting the first signs of luuuurve.
Hero is in on the plan to get Beatrice and Benedick together. While Beatrice is within listening range, Hero and her attendant Ursula play the same old trick on Beatrice. They announce that they can’t tell Beatrice of Benedick’s love because no man can ever please Beatrice, she’s such a proud and scornful woman. Once they leave, Beatrice (surprise!) has the same reaction as Benedick, and promises she’ll leave her scorn behind. She’ll love and marry Benedick, if he’ll have her.
Later, Don Pedro and Claudio are with Leonato and Benedick, and they launch into teasing Benedick, who’s really changed by his crush—he has a shaved beard, he smells nice, and his wit is blunted—he’s already a milquetoast. Benedick can’t handle the teasing, and scampers off, leaving Don Pedro and Claudio to be approached by Don John. Don John claims Hero is disloyal, and he can show them proof. Claudio says if he finds Hero is disloyal, he’ll disgrace her in front of the whole congregation... which is a tad overly dramatic in our opinion.
Later that night, Dogberry, a constable, and his man Verges give muddled instructions to an incompetent group of watchmen, who plan to sleep through their duties. In spite of their incompetence, they hear Borachio recount to Conrade (another of Don John’s evil cronies) how Don John’s scheme went off without a hitch. Margaret appeared to be Hero and flirted with Borachio, while Don Pedro, Claudio, and Don John witnessed "Hero’s" disloyalty. Claudio has decided that he’ll renounce Hero tomorrow morning at the chapel. The watch then comes forth and arrests Borachio and Conrade for their wickedness.
It’s the morning, and Hero is getting ready for her wedding. Beatrice is helping her, although Beatrice isn't acting like her usual jovial self. Margaret teases that Beatrice looks like she’s in love. Just before the wedding can take place, Dogberry comes to Leonato, trying to get him to come to the examination of the captured prisoners, Borachio and Conrade. Leonato is in a rush to get to his daughter’s wedding, so he tells Dogberry to do the examination himself.
Finally, everyone’s ready for the wedding, except Claudio, who proceeds to call Hero a disloyal, deceptive, and faithless whore in front of the entire group that’s come to watch her get married. Hero denies Claudio’s claims that she was flirting with another man at her window, but Don Pedro says he definitely saw her too, as did Don John. Hero faints. The men stalk out, leaving the girl for dead, and everyone else tries to sort out just what in the world is going on.
Beatrice and the Friar are certain there’s some treachery afoot, and Benedick realizes Don John must be at the bottom of this. The Friar then comes up with a strategy—they’ll let word get out that Hero actually did die. People will then pity the girl, and forget this bad little groomzilla episode. Claudio will once again remember Hero fondly (once she’s dead) and in the meantime, some proof will probably surface that will clear her good name. If nothing shakes out, they can always send Hero off to a convent to be cloistered away.
Everyone leaves except Benedick and Beatrice. Benedick takes advantage of this really awkward moment to profess his love for Beatrice. She’s stoked, and says she loves him too, but she’s pretty preoccupied with her cousin’s ruin. However, if Benedick wants to prove his love to her, he should kill Claudio for slandering Hero. At first, Benedick tries to backtrack out of it, but Beatrice threatens to leave. Benedick comes around to thinking Claudio really has wronged Hero, and he goes off to challenge Claudio.
Meanwhile, back at the ranch (just kidding, the prison), Dogberry is interrogating Borachio and Conrade. He trips up the investigation, but the Sexton (the guy who’s documenting the whole process) manages to piece together that they’ve found the source of Hero’s ills. The Sexton is off to report the news to Leonato, with the prisoners in tow. Leonato and Antonio confront Don Pedro and Claudio, saying they’ve killed an innocent girl by wronging Hero.
Claudio and Don Pedro, however, stick to their guns; they maintain they’ve done nothing wrong, they only exposed Hero as a harlot—it's not their fault that she's now a dead harlot. Next, Don Pedro and Claudio then run into Benedick. Benedick challenges Claudio to a duel for causing the wrongful death of an innocent girl. He calls Claudio a young punk, saying he’s waiting for the challenge whenever Claudio is ready.
Claudio and Don Pedro joke about Benedick until Dogberry comes in with Borachio and Conrade in tow. Borachio admits that he and Don John are responsible for framing Hero, and now the innocent girl is dead. Claudio and Don Pedro are shocked. So Claudio and Don Pedro are sorry they killed a girl by calling her a harlot, and Leonato enters, having heard the same news. Claudio says he and Don Pedro are to blame as much as Borachio and Don John... because they believed the slander against Hero.
Leonato says Claudio can make it up to him by going to Hero’s grave and mourning her with an epitaph (a statement in memory of a deceased person), to be hung on the family tomb. That should clear Hero’s name to the public. After that, Claudio is to meet Leonato at the house, and marry Antonio’s daughter, who is apparently the spitting image of Hero.
During this time, Benedick and Beatrice have been flirting around in the orchard. Beatrice hears that Benedick challenged Claudio and is waiting for an answer, and she won’t make out with Benedick until he’s got some blood on his hands. Thankfully, before anyone can get their hands into some flesh, Ursula rushes in to announce that Hero’s name has been cleared.
That night, Don Pedro and Claudio go to Hero’s tomb, where they hang an epitaph and mourn. Claudio promises he’ll do this ritual once a year on the anniversary of Hero's death. Thankfully, it’s a new day, and they can get over all this sadness about Hero and get to Claudio’s new wedding. At Leonato’s house, everyone’s stoked that things worked out so nicely. The newly exonerated Hero and all the girls are sent off to cover their faces, and Benedick pulls the Friar aside to ask for his services in marrying him to Beatrice after the whole "Hero’s risen from the dead" hubbub.
Don Pedro and Claudio enter. Claudio agrees to marry Leonato’s niece before he’s even seen her. Then, he sees her, and realizes she’s actually Hero!
As everyone is about to head off to the chapel, Benedick makes a big public show of calling out Beatrice, asking if she loves him, maybe. Beatrice, embarrassed, basically says "Um, I love you in a friendly, non-sexual manner. Of course I don’t want to marry you, because that would make me a hypocrite for saying all the time how stupid marriage is." Benedick says (totally paraphrased) "Oh, friends are fun, I like having more friends."
Then Claudio and Hero blow Beatrice and Benedick's cover by revealing love notes the two had written to each other, and Benedick and Beatrice say, "Aw shucks, guess we’ll have to get married after all... but it’s only because we pity each other and don’t want to die old and alone."
Then Benedick declares he doesn’t mind getting married after all, as people change their minds all the time about who they really are. Benedick also announces that he and Claudio are friends again, and everyone takes to dancing before they’re even married. The end.