In another part of Leonato’s house, Don Pedro, Claudio, Benedick, and Leonato are all gathered.
Don Pedro says he’s only sticking around until Claudio is married, and then he’s off back to Arragon. Claudio volunteers to come with him, but Don Pedro points out that Claudio will have more interesting things to do on his wedding night.
Instead of Claudio, Don Pedro looks forward to Benedick’s company. Don Pedro then makes some heavy-handed references to the fact that Benedick can be trusted to never fall in love. This would seem like a random thing to say, except we know Don Pedro’s trying to egg Benedick on into being in love.
Benedick is then like, "Well, guys, I’m going through some special changes." And knowing what we know about special changes, they’re a perfect invitation for mockery and derision.
While Claudio and Don Pedro tease Benedick mercilessly for seeming lovesick, Leonato notes that he looks sadder.
They offer all sorts of cures for his ache. Then they note that he’s gotten a haircut, is wearing cologne, and his beard has been shaven off and the hairs sent to fill tennis balls. (Random!) Anyway, with all these changes, either Benedick is in love, or he’s been transformed into a metrosexual.
They tease that his melancholy and newly subdued nature are sure signs of his sighs over a girl, and they figure that if any woman loves him, it’s only because she doesn’t know him very well.
Then there’s some taunting about how the girl Benedick loves will die for him, but she’ll die with her face upward. ("Die" is Elizabethan slang for orgasm – yet another cheap sex joke, courtesy of William Shakespeare).
Benedick shrugs off all this teasing and asks Leonato to go off with him to talk about serious stuff.
Don Pedro and Claudio are then conveniently left alone for Don John to prey upon.
Don John confirms that Claudio means to get married the next day, and then he’s like, "Well maybe you won’t want to get married tomorrow after you fall into my evil trap." But he doesn’t say that because then it wouldn’t be much of a trap, would it?
Anyway, Don John builds the melodrama by saying they might hate him for what he has to say, but they should wait until after hearing his news to pass judgment on him. Don John claims that Don Pedro’s efforts for Claudio’s wedding were sadly misguided: Hero is disloyal. Not only is she disloyal, he could call her all sorts of other nasty names, but he doesn’t.
Instead, he’ll let the seed of suspicion sprout in Don Pedro and Claudio until he can bring them to Hero’s window at midnight. There, he promises them they’ll see a man in Hero’s bedroom. After that, if Claudio still wants to marry, he can, but at least he’ll know what he’s signing up for.
Claudio pledges that if he sees anything unseemly tonight, he’ll be sure to be as dramatic as possible, by denouncing Hero in front of the whole wedding party tomorrow (instead of sending her a simple, informative, "It’s over" via text and changing his Facebook status).
Don Pedro pitches in that he’ll help Claudio disgrace Hero at the wedding if there’s proof of her disloyalty tonight. After all, he’s responsible for getting the two of them together in the first place.