After Ba Sing Se's fall, Princess Azula decides to return home to the Fire Nation with Prince Zuko and their imprisoned uncle, Iroh. When Zuko refuses to leave, Azula and Ty Lee form a plan to convince him to go with them.
As Iroh sits in his Ba Sing Se jail cell, two guards lament the tragedy of the Fire Lord's own brother being treated in such a way. Zuko, although for a moment having seemed distraught about the his uncle's treatment, berates them for saying such a thing about a Fire Nation traitor and orders them to get back to work. Later on, he visits Azula in what was the Earth King's throne room hours earlier. She tells him that the arrangements have been made for them to return to the homeland and that they will be headed there by the next night. Despite Azula's assurance that Ba Sing Se will be left in good care with Joo Dee at the helm, Zuko asserts that he will not go and storms out of the room.
Azula, believing that Zuko is making things difficult, visits Ty Lee and alerts her of the situation. With the knowledge that Mai and Zuko had childhood crushes on one another, Azula reveals to Ty Lee that getting them to know each other again will solve their problem. A while later, Azula is commanding a few Dai Li to set a dinner table for two. When Zuko and Mai arrive, although knowing they have been tricked into eating together, sit down and begin to dine. They leave the table after Zuko points out that Azula and Ty Lee are spying on them.
While walking through the streets of Ba Sing Se, Jin recognizes her old date "Lee", which is the name Zuko used on his night out with her. In order to avoid an awkward situation, he says that Mai is simply the knife thrower from the circus. Apparently intrigued by this fantasy, Mai decides that she will demonstrate her skills for Jin by throwing a pointed icicle through a fish resting on Zuko's head, which she accomplishes. When Mai offers for Jin to try it herself, she does so, but misses the intended mark and sends Zuko toppling into the Firelight Fountain.
A heartfelt conversation makes it plain to Zuko and Mai that they have feelings for each other. They reminisce about old times before sharing a kiss. The next morning, Mai asks hopefully if Zuko will be returning with her to the Fire Nation. To her request, Zuko almost declines, but Azula mentions how unfortunate Iroh is and that he may not survive the trip to the mainland. Upon hearing this, Zuko makes up his mind: he will return to the Fire Nation. Azula comments on how it was no one's decision but his own.
The plot of "Going Home Again" takes place concurrently with the events of Escape from the Spirit World, which follows Aang while he is unconscious, and "The Bridge", which follows the fate of Team Avatar after the fall of Ba Sing Se.