The gang arrives at Kyoshi Island and are captured by some Kyoshi warriors. When Aang reveals that he is the avatar, news quickly spreads out, eventually reaching Zuko, who then goes to Kyoshi Island to capture him.

To contact the spirit of the previous Avatar, Aang must reach a temple in the Fire Nation before the sun sets on the following day. There he will learn what he must do to restore balance to the world. Zuko must defy his banishment to follow Aang.

While on their way to the North Pole, Aang and his friends arrive at a giant canyon where two groups of refugees are bickering over who should get to go across. Aang decides to walk across with the two groups to ensure they don’t fight one another. However, he soon learns that the two tribes have been feuding for one hundred years and they both believe their actions are justified. But when the predators inside the canyon start to come out, Aang is stuck trying to defend both tribes from each other and the vicious wildlife.

Aang feels neglected as Katara and Sokka reunite with Bato, an old friend of their father’s from the South Pole. They begin to reminisce on their times in the past while they wait for a message to arrive from their father. Aang believes Katara and Sokka will abandon him and go out to find their father should the message arrive. However, when the messenger gives Aang the message to give to Bato, Aang betrays his friends in a way Katara or Sokka could never imagine. However, when Zuko recruits a bounty hunter named June to track Aang down, his friendship is put to the test as he must deal with the fact that he betrayed his friends while defending himself from yet another fight.

When Aang tries to find the north pole, he is found by the north pole instead. As they are taken there, Aang and Katara are eager to find a waterbending master, only to discover that girls are not allowed to learn waterbending.

Plagued with nightmares featuring the devastating power of his Avatar State, Aang and the gang meet an Earth Kingdom general who has big plans for defeating the Fire Nation. Meanwhile, Zuko and Iroh, having survived the failed attack on the North Water Tribe, have a surprise visit from Zuko's sister with seemingly good news.

A mysterious tornado pulls the kids into a supernatural swamp where Katara, Sokka and Aang have mysterious visions. Meanwhile, Momo and Appa are chased by rogue swamp dwellers and only Aang and the gang can save them.

Tired from trying to escape a machine that shows up every time they try to sleep, Aang and the gang have to escape Azula and her team, but their exhaustion leads to a tight situation. Meanwhile, Zuko must deal with something personal, and Iroh bonds with an unlikely individual.

When Aang and his friends find a professor who knows of a library that contains information about the world, Sokka decides to go there to hopefully find some information to use against the Fire Nation. The library is guarded by the knowledge spirit, Wan Shi Tong, who doesn't welcome humans into his library, because he believes they only seek information for evil purposes. When Wan Shi Tong discovers Sokka wasn't being truthful with him, he begins to sink the library, bringing the kids down with it.

Having made it to the outer wall of Ba Sing Se, the kids confront a Fire Nation army that is driving a massive Fire Nation drill, which poses an imminent threat to the last Earth Kingdom stronghold. Meanwhile, Zuko and Iroh make crucial mistakes which begin to attract Jet's suspicions.

Appa's journey from being abducted in the desert to the present is explored.

Aang travels to the Eastern Air temple to receive guidance from Guru Pathik while Sokka is reunited with his long-lost father. Meanwhile, Azula has something diabolical in store for her enemies in the Earth Kingdom, including Zuko and Iroh.

Aang awakens to find himself aboard a captured Fire Nation ship with a full head of hair and sustaining serious injuries from the previous battle for Ba Sing Se. At his side are Katara, Sokka, and their father Hakoda who recount the events that led the four to the ship and contemplate their next move. Aang struggles to fight his own desire to face the Fire Lord before he is ready. Meanwhile, Zuko deals with his own issues as he makes his long-awaited journey home, with the fear of his father's rejection hanging over his head.

Feeling as though he isn't contributing enough to the group, Sokka seeks out an elusive swordsmaster from whom he can learn the ways of the blade.

When Katara expresses her disapproval of Toph's new way to make quick cash, the group finds her too motherly and tension grows between Katara and Toph. When Katara finally decides to participate in this scam to disprove Toph's accusations, they are left vulnerable and are forced to face the dire consequences.

The day of the eclipse has arrived, and the invasion force gathers together to make last preparations. They infiltrate the island and the battle begins. Meanwhile, Aang searches for the Fire Lord.

While teaching Aang firebending, Zuko realizes that he has lost all his firebending skills. To regain his powers, Zuko and Aang must seek the original source of firebending within the ruins of a lost civilization.

A play recounting the gang's adventures does not sit well with Aang and his friends, except for Toph who enjoys it very much. Meanwhile, Aang confesses his love to Katara, but the response is ambiguous.

While on the island, Aang seeks guidance from his past lives, but is not pleased with what he is told. The island, in fact, turns out to be a lion turtle from which Aang is given the guidance he had been seeking. After the tracker is unable to track Aang, the rest of the group decide they must find Iroh. Meanwhile, while tracking down Iroh, the group meets up with The Order of the White Lotus, a group that transcends the division of the four nations.