Kate is tamed, and Vincentio makes an appearance.
Characters: 
Petruchio

Petruchio successfully tames Kate, and then invites Vincentio to accompany them to Padua. 

Katherina

Katherina finally decides to agree with everything Petruchio says. 

Hortensio

Hortensio accompanies the newlyweds on the road back to Padua, where he plans to marry a widow he knows. 

Vincentio

Vincentio runs into Petruchio, Kate, and Hortensio on the way to Padua, and learns of his son's marriage to Bianca. 

Scene Summary: 

Petruchio, Kate, and Hortensio are on the road from Verona to Padua, and Petruchio is still testing Kate’s willingness to agree with whatever he says, even if it means calling the sun the moon. Petruchio mentions how bright the moon is, and Kate tells him it’s the sun. Petruchio threatens to turn back home if Kate doesn’t stop contradicting him, and Hortensio gives Kate the advice to agree with whatever Petruchio says, or they’ll never make it to Padua. Kate gives in and says it can be the moon. This seems to be the breakthrough Petruchio’s been looking for, and Hortensio congratulates him as if he’s won a war.

Just then, an older man joins them, and Petruchio decides to continue his testing of Kate by calling the man a young lady. Kate plays along, complimenting her beauty, but then addresses him as an old man as soon as Petruchio does. Then the man introduces himself as Vincentio of Pisa — the real father of Lucentio. Petruchio tells Vincentio that Lucentio has married Bianca, Kate’s sister, assuring him that it’s a good match. They decide to travel to Padua together, and Hortensio stays back just long enough to tell us that he thinks Petruchio has taught him how to tame a wife, which gives Hortensio the courage to marry the widow now.