Leonato has noticed that Don John did not attend the dinner, but Hero tells them he is melancholic. Beatrice says that a combination between Don John and Benedick would create the perfect man, one who spoke just enough. Leonato tells Beatrice she will never get a husband if she continues to make such "shrewd" remarks. Beatrice acknowledges that she is happy without a husband and plans to die a spinster.
Antonio turns to Hero and tells her he hopes she will obey her father, but Beatrice interrupts him and mocks his expectation that Hero will curtsy to her father's every demand. Ignoring her, Leonato orders Hero to accept the Prince's offer if he comes to her. Beatrice gives Hero some advice about how to accept, telling her how to make the Prince wait for an answer and comparing wooing, wedding and repenting to various dances. Leonato tells Beatrice, "Cousin, you apprehend passing shrewdly" (2.1.67).
Don Pedro and the other revelers arrive wearing masks. He immediately goes over to Hero and asks her to dance a with him. She agrees, but tells him she hopes the face underneath the mask is far better looking than the mask itself. Meanwhile, Balthasar, the servant to Don Pedro, has approached Margaret, a serving-gentlewoman to Hero, and they flirt briefly. Antonio and Ursula form another couple on the dance floor, and Ursula tells him she recognizes him as Signor Antonio. Antonio tries to deny it, but she refuses to believe him.
Benedick meets up with Beatrice and refuses to reveal who he is. She starts to talk about Benedick, calling him, "the Prince's jester, a very dull fool" (2.1.118). Benedick assures her he will inform Benedick what she has said about him.
Don John and Borachio figure out who Claudio is by his bearing. Don John approaches him and asks him if he is Benedick, and Claudio plays along, claiming he is. Don John tells Claudio that he should separate Don Pedro and Hero because she is not equal to his brother's birth. Borachio chimes in as well, telling Claudio that he heard Don Pedro swear his affection for Hero and plan to marry her that very night.
Once Claudio is alone he comments that it must be true since friendship is constant in all things except for love. He remarks, "Farewell, therefore, Hero" (2.1.160). Benedick arrives and invites Claudio to go with him, telling him the Prince "that got your Hero" (2.1.169). Claudio, depressed by the thought that Don Pedro has stolen Hero from him, leaves. Don Pedro himself arrives and Benedick accuses him of betraying his friendship to Claudio by stealing Hero. Don Pedro denies the charge and says that he was merely doing what he could for the couple.
Benedick has been stung by what Beatrice said about him while they danced, and the he tries to tell Don Pedro what she said that hurt him. He is mostly upset because she called him the "Prince's jester", yet he ironically confirms this accusation by comically reenacting the scene for Don Pedro. Beatrice arrives with Hero, Claudio and Leonato. Benedick leaves as soon as he sees her, unable to bear her comments any longer.
Don Pedro chastises Beatrice for having been so harsh to Benedick, but she replies that Benedick once won her heart and toyed with her. He then turns to Claudio, who is still jealous of him, and informs Claudio that he wooed Hero successfully and spoke with Leonato who consented to the marriage. Neither Claudio nor Hero are able to speak to one another, and finally Claudio says, "Silence is the perfectest herald of joy" (2.1.267).
Beatrice remarks that everyone is getting married and leaving home except she herself. Don Pedro gallantly offers to marry her but she refuses, telling him he is "too costly to wear every day" (2.1.287). She leaves after Leonato reminds her of some work she needs to take care of. Claudio and Leonato agree to hold the wedding in one week, and in the meantime Don Pedro tells them they will contrive to get Benedick and Beatrice to fall in love. Claudio and Hero agree to participate in the plot.