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.