Weeks after the fall of the Earth Kingdom, Aang and his friends must infiltrate the Fire Nation. Katara meets her father for the first time in years. Zuko returns home, but is uneasy with his newfound reputation.

Posing as a regular kid, Aang goes to a Fire Nation school and sees what's missing from their lives. Zuko visits his uncle in prison.

When Aang and his friends come across a fishing village being poisoned by a nearby factory, a local legend comes to life to help the townspeople.

After deciding he's the least valuable member of the team, Sokka seeks an apprenticeship with a sword-master. The rest of the gang tries to adjust to being without him. The imprisoned Iroh may not be as beaten as he seems.

On a forced vacation, Zuko, Azula, Ty Lee and Mai try to blend in with normal teenagers and learn about themselves and one another. Aang and company are attacked by an ominous assassin.

Both Aang and Zuko must learn the history of how the war began. Zuko learns a secret about his great-grandfather's past.

When Toph discovers a quick way to make cash, Katara disapproves, and the rift between them has disastrous consequences.

Creepy things are afoot when the gang meets a mysterious old innkeeper with a secret.

As the invasion approaches, Aang has recurring nightmares about being unprepared to face the Firelord. Zuko feels the perks and pressures of being the prince again.

Zuko makes a decision about his future. Aang reunites with many of his old friends in a full-scale invasion of the Fire Nation capitol to coincide with an eclipse which will remove the Fire Nation's powers.

The invasion seems to be succeeding until Aang learns that their arrival was anticipated. Zuko confronts his father.

The gang hides out in the Western Air Temple. Zuko tries to convince the gang of his change in heart, but they are very hesitant. Combustion Man/Sparky-Sparky Boom Man attacks again.

Zuko has joined up with Aang's group and is now ready to teach Aang fire bending. Unfortunately, Zuko has found out that he has lost his ability and must now relearn it. Zuko and Aang travel to find the original source of fire bending.

Sokka and Zuko head to the Fire Nation's most heavily guarded prison, the Boiling Rock, in hopes of finding and breaking out the captured invasion force.

The escape is planned and the heroes attempt to break from the prison that very day. But problems come when Azula, Mai and Ty Lee arrive at the prison.

Trying to prove that she can trust him, Zuko helps Katara track down the man who killed her mother.

The gang, now hiding at Ember Island, watch a play about themselves and their adventures.

Sozin's Comet is only three days away. Zuko tells the others what the Fire Lord plans on the day of the comet and the gang realizes that they must stop him before then. But Aang doubts that he can do what is expected of him.

Aang awakes on a mysterious island and confronts his past lives for advice on how to stop the Fire Lord without killing him. The rest of the group searches for Aang.

Zuko battles his sister with Katara's help for the right to be named Fire Lord. Elsewhere, Aang meets Ozai just as the comet arrives.

Aang's moment of truth arrives. Can he defeat Ozai, the Phoenix King? Will he be forced to take a human life? All the characters face their greatest challenges.