Lucentio welcomes his guests to the wedding banquet and everybody hangs out and shoots the breeze, which involves a lot of trash talk, of course.
Petruchio says Hortensio is afraid of his wife, the Widow, so the Widow chimes in and says Petruchio is crazy – he's the one who is afraid of his wife, Kate.
Kate confronts the Widow but doesn't shrew out and pull her hair or anything. Seeing his wife in a verbal smack-down with another woman gets Petruchio excited – he cheers on Kate like he's at a bear baiting. (History snack: Bear baiting is an Elizabethan blood sport where a bunch of people get together and watch a pack of dogs tear into a bear that has been chained up.)
When the women leave the room, the guys continue their little contest. Petruchio bets Hortensio and Lucentio twenty crowns that his wife is the most obedient.
The fellas say they'll take that bet and they send a servant to fetch their wives.
Lucentio and then Hortensio look like chumps when Bianca and then the Widow say they're too busy to stop what they're doing for their husbands.
When Petruchio sends for Kate, she comes a-runnin' and asks Petruchio how she can serve him. Petruchio orders Kate to fetch the other wives and, to everyone's surprise, she does.
Baptista is shocked. He says he doesn't recognize his own daughter, so he's going to give Petruchio another dowry since it seems like Petruchio has married a new and completely different woman.
Petruchio goes on showing off and tells Kate to take off her ugly hat. Kate throws her hat on the ground.
When Petruchio tells Kate to put the unruly wives in their proper places, Kate does that, too. She delivers the longest speech in play, which is all about how men are like kings and women are like their subjects – women should obey a man's every command. She also says husbands work hard to protect their wives, so women should be obedient. Bianca and the Widow, she says, are a disgrace to wives everywhere.
Then, Kate kneels down and fondles Petruchio's feet while saying something like "You're the king, baby."
Petruchio kisses Kate and says let's go to bed, baby. Then, he turns to the other men and brags that he's the man – he's landed a rich, obedient wife, and he just took an easy 40 crowns from a couple of suckas.
Kate and Petruchio run off to bed, presumably, to make love and then live happily ever after (maybe). The wedding guests stand around with their mouths hanging open.