Sokka and his sister Kya - later renamed Katara, must travel the world to find masters for Aang, who is the Avatar. However, they must evade a critical foe, Prince Zuko of the Fire Nation, who wants to capture Aang.

The legend of the Avatar is told. Katara and Sokka find a strange boy within an iceberg.

Aang and Katara inadvertently set off a trap the brings the warmongering Fire Nation to the Southern Water Tribe's peaceful village at the South Pole.

After his departure from the Southern Air Temple 100 years ago, an excited Aang finally returns home but is disillusioned by what he finds there.

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 and suddenly reaches to Prince Zuko who then goes to Kyoshi Island to capture him.

Aang's abilities as an airbender are challenged by a king.

In a nearby Earth Village, the gang meets a teenage earthbender named Haru. This village lives in fear of the Fire Nation, for soldiers there capture any earthbenders they can find.

Aang and friends visit a village being terrorized by an angry spirit. Iroh is captured by Earth Kingdom soldiers.

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. Zuko must defy his banishment to follow Aang.

Katara, desperate to improve her abilities and teach Aang, steals an expensive waterbending scroll from pirates, causing them to pursue the group.

Aang, Katara, and Sokka have their friendship tested by a charismatic Rebel Leader who is fighting against the Fire Nation.

Aang is tested as the Avatar when he must help two feuding clans cross a dangerous canyon peacefully.

Aang relives the events after finding out that he is the Avatar 100 years ago and tells them to Katara, while Iroh tells the story of Zuko's scar and banishment to the crew.

When Aang is captured by the Fire Nation, his only hope is a mysterious masked figure.

The gang visits a village where a fortuneteller lives who is said to never be wrong. Aang tries to show Katara how he feels about her.

Sokka and Katara meet a friend of their father who offers to take them to join the Water Tribe's navy. Aang fears his friends will choose seeing their father again over staying with him.

When he meets an outcast from the Fire Nation, Aang is impatient to skip ahead in his training.

Aang is upset when he finds an old Air Temple has been desecrated by an old inventor and his son.

The heroes finally arrive at the North Pole. But for Katara, the trip may have been in vain, as Master Pakku refuses to teach girls waterbending.

While Katara herself becomes a great waterbending master, Commander Zhao plans a siege on the Northern Water Tribe. Meanwhile, Sokka's on a mission to stop this siege while Aang tries to buy them some time.

As the Fire Nation continues its assault on the Northern Water Tribe, Sokka, Katara and Yue set out on a search for Aang, being guided by his spirit.