When a young waterbender, named Katara, and her brother, Sokka, discover a giant iceberg while fishing for food around their homestead at the South Pole, they discover that there is a boy, named Aang, inside.
After Aang accidentally sets off a Fire Nation trap, he is banished from the South Pole. Soon after Prince Zuko attacks the Southern Water Tribe seeking to capture the Avatar. Aang returns and surrenders to save the Water Tribe.
Aang is eager to take Sokka and Katara to the Air Temple where he was raised. But upon arrival, it becomes apparent that the temple is not at all how Aang remembers it.
As one of Aang's little detours, the group heads toward the island of Kyoshi. But soon they learn that the townspeople don't trust foreigners at all; however, when Aang proves to them that he is the Avatar they are treated as guests of honor.
Aang takes Katara and Sokka back to a favorite place he used to go to when he was younger, the Earth Kingdom City of Omashu. But when they break the law they are taken to the King to get their punishment.
The kids come to an Earth Nation town which is occupied by the Fire Nation. But will Katara’s attempts to inspire the oppressed people help them or hurt them?
Aang, Katara, and Sokka arrive at a town being terrorized by a mysterious force from the spirit world. Aang doesn’t know how to help these people, and realizes he has much to learn about being the Avatar.
During the winter solstice, Aang must reach a Fire Nation temple while dodging Prince Zuko, Commander Zhao, and the Fire Sages who guard it.
After Katara attempts to teach Aang waterbending, she is desperate to improve her abilities.
While traveling towards the North Pole, the group almost gets captured by the Fire Nation.
When Aang and friends come to the rim of a giant canyon, they are asked to help guide two groups of refugees across.
A powerful storm brings up painful memories of the past – and puts everyone in jeopardy in the present.
After Sokka and Katara get sick due to being in the storm, Aang seeks out a cure and discovers he needs some frozen frogs in order to get them cured.
Aang, Katara, and Sokka discover a village of people who are all reliant on a fortuneteller in their everyday lives – but they are so reliant that they are blind to the immanent danger they are all in.
Aang feels insecure when Katara and Sokka come across something that reminds them of home. Because Aang thinks his friends might leave him, he hides an important message which only leads to trouble.
Aang attempts to find a Firebending master to teach him while Katara learns that she possesses a special power.
After hearing rumors about surviving Airbenders, the kids journey to the Northern Air temple to see for themselves. What they find there could spell disaster for all enemies of the Fire Nation.
The kids reach the Northern Water tribe, and Aang and Katara look for a Waterbending Master as Sokka falls for a princess. Meanwhile, Zhao plans an attack and Zuko must find a way to continue his quest for the Avatar.
The Northern Water Tribe braces itself for an attack by Admiral Zhao’s Fire Navy fleet. In the heat of battle, Aang struggles to defend the city. He wonders if there isn’t a better way to use his Avatar abilities.
Zhao’s invasion breaks through the outer wall of the Northern Water Tribe’s defenses, and he reveals a sinister plan.
Aang and the group meet an Earth Kingdom general who wants to use Aang's powerful "Avatar State" as a weapon to defeat the Fire Nation. But getting into the "Avatar state" on purpose is more difficult than Aang thinks.
On their way to Omashu, the kids meet a group of nomads who show them a short cut through the 'cave of two lovers'.
The kids return to Omashu so that Aang can learn Earthbending from King Bumi. But when they get there, they are shocked to find the city is now in Fire Nation hands. Despite the danger, Aang enters Omashu in search of King Bumi.
When the kids end up in a mysterious and strange swamp, their fears are exposed. And Aang learns about being "connected to the Earth" from an unlikely teacher.
Aang must clear up a wave of anti-Avatar sentiment and atone for something he did in the past.
In search for an Earthbending teacher for Aang, the kids go to an underground Earthbending tournament where they encounter Toph, a blind, but powerful Earthbender.
Traveling without Uncle now, Zuko wanders alone into an Earth Kingdom town where he bonds with a local boy. Meanwhile, Zuko is haunted by memories of his own youth.
As the kids are pursued relentlessly by a mysterious machine, their exhaustion puts them at each other's throats.
When Aang struggles with a block while trying to learn Earthbending from Toph, he wonders if the problem is with him or his teacher. Meanwhile, Sokka gets himself in a jam.
A professor leads the kids to a spirit library in the middle of the desert, where Sokka hopes to discover powerful secrets to use against the Fire Nation.
Aang searches for Appa, while Katara struggles to keep everyone together so they can survive in the vast desert. Meanwhile, Uncle and Zuko seek help from an ancient secret society.
The group then huddles around the map to discuss in which direction they should go – the Serpent's Pass appears to be the most direct route.
Aang discovers a secret Fire Nation super weapon heading straight for Ba Sing Se and must stop it before it destroys the great wall that protects the city from invasion.
Aang and the kids finally arrive in Ba Sing Se to see the Earth King, only to find mysterious forces within the city conspiring to stop them. Meanwhile, Jet tries to find proof that Zuko and Uncle are Fire Nation.
A series of short stories, highlighting different characters and their individual adventures in the city. Tales of Katara and Toph, Uncle, Sokka, Aang, Zuko, and Momo.
In this special episode, we go back in time to the moment Appa was stolen, and find out exactly what happened to him, and where's he's been all this time - and where he is now!
While searching for Appa, the kids run into Jet, but are torn about whether to trust him or not. Meanwhile, Zuko also hunts for Appa.
The kids battle Long Feng the Dai Li when they attempt to show the Earth King the vast conspiracy taking place in his city. Zuko becomes seriously ill and has feverish dreams as he faces a spiritual crisis.