Season one (Book 1: Water)

Katara, a fourteen-year-old Southern Tribe Waterbender, and her older brother Sokka find the iceberg containing Aang and Appa and freed them. Aang learns of the war occurring in his absence, and the siblings join him to reach the Northern Water Tribe at the North Pole, so that he and Katara can learn Waterbending from a master. Aang's return attracts the attention of prince Zuko, the exiled son of Ozai, who needs to capture the Avatar to return to his homeland. Aang is also pursued by Zhao, a powerful Fire Nation militant who intends to win Ozai's favor and rob Zuko of his redemption.

En route to the North Pole, Aang meets the Kyoshi Warriors and his childhood friend Bumi, attempts to learn fire bending from the deserter fire bending master Jeong Jeong, and gains a traveling companion in a winged lemur he names Momo. Aang discovers the genocide of his people while visiting the Southern Air Temple. During the winter solstice, Aang meets his past life Avatar Roku. Roku tells him of an astral body called Sozin's Comet, which enabled the genocide of the Air Nomads. Aang learns that he must master all four elements and stop Ozai before the comet returns at the end of summer.

Once at the Northern Water Tribe, Aang and Katara learn advanced Waterbending from the wise Master Pakku, while Sokka falls in love with Princess Yue, the tribal chief's daughter who was stillborn before given life by the Moon Spirit. However, Zhao lays siege to the Northern Water Tribe. During a full moon, he targets the mortal forms of the Ocean and Moon Spirits, the source of waterbending, capturing the latter and causing a lunar eclipse. Though the group and Iroh attempt to convince him otherwise, Zhao kills the moon spirit to render the waterbenders powerless. Aang uses his Avatar State and combines with the enraged Ocean Spirit to drive off the fleet before Princess Yue sacrifices her life to revive the Moon Spirit. Though its mate is revived, the Ocean Spirit exacted its revenge on Zhao after separating from Aang. Soon after, word of Zuko and Iroh's actions during the siege of the Northern Water Tribe reaches Ozai, leading him to believe they are both worthless to the Fire Nation, and he decides to send his daughter, Zuko's gifted yet sadistic sister Princess Azula, to find the now wanted Zuko and Iroh.

Season two (Book 2: Earth)

After leaving the Northern Water Tribe, Aang continues Waterbending under Katara's tutelage as the group begins looking for an Earthbending teacher. Their search brings them to Toph Beifong, a twelve-year-old blind tomboy and an Earthbending prodigy who wants independence from her upper-class family. Now wanted fugitives, pursued by Azula as she also hunts down Aang's group, Zuko and Iroh attempt to lead new lives in the Earth Kingdom capital of Ba Sing Se. Eventually, finding the library of the spirit Wan Shi Tong, Aang and his group learn that an imminent solar eclipse could allow them to stop the Fire Nation before Sozin Comet's arrives. However, their journey to Ba Sing Se to inform the Earth King of this is complicated when Appa is kidnapped and, managing to reach the city, find the Earth King Kuei and the Ba Sing Se manipulated by Long Feng, the leader of the Dai Li secret police.

After Aang's group finds Appa and exposes Long Feng, the group temporarily go their separate ways. Toph ends up getting captured, but escapes by inventing metalbending, while Aang attempts to learn to consciously access the Avatar state. The Dai Li join Azula to instigate a coup d'état of Ba Sing Se and Zuko, having tried to put the past behind him, relapses at the last second when the Avatar appears in order to rescue Katara. As Aang tries to enter the Avatar state, Azula nearly kills him, which blocks this ability. With Ba Sing Se and the Earth Kingdom now under Fire Nation rule, the group escapes thanks to Iroh covering them at the cost of his freedom, and Kuei goes into hiding.

Season three (Book 3: Fire)

Aang recovers from a long coma to find his friends and allies disguised as soldiers on a Fire Nation ship. Though reluctant, Aang is forced to maintain the rumors of his death to ensure the success of a planned invasion of the Fire Nation with their allies. Despite winning back his father's love, as Azula gave him the credit for the Avatar's apparent death, Zuko becomes guilty of his actions while learning from Iroh of his heritage as the great grandson of Roku on his mother's side.

While the invasion meets great success at first, Aang and his friends are unable to find Ozai and are forced to retreat with many of their allies captured. At the same time, having learned of his father's intention to wipe out the Earth Kingdom at the time of Sozin's Comet, Zuko leaves the palace to teach Aang Firebending. Though distrusted at first, Zuko is eventually accepted by the group, and they are joined by the Kyoshi Warriors' Suki. But as the day of the comet approaches, Aang became conflicted with the notion that he needs to kill Ozai and mysteriously disappears.

As Ozai christened himself the "Phoenix King" while making final preparations, Katara and the others unsuccessfully search for Aang. They instead find Iroh after he escaped during the Day of Black Sun, joined by the other members of a secret society called the Order of the White Lotus: Bumi, Master Pakku, Jeong Jeong, and Master Piandao (a master swordsman who taught Sokka). Together, they liberate Ba Sing Se. Sokka, Toph, and Sukki leave to hinder the Fire Nation airships, while Zuko and Katara travel to the Fire Nation capital to prevent Azula from being crowned the new Fire Lord. Though having become mentally unstable since her friends Mai and Ty Lee stood up to her with Ozai leaving her behind worsening it, Azula maintains her resourcefulness when challenged by Zuko to an Agni Kai duel by forcing him to intercept a lightning bolt meant for Katara. Luckily, Katara manages to incapacitate Azula before healing Zuko.

At the last second, as Sozin's Comet appears, Aang confronts Ozai. Aang finds himself in a losing battle until Ozai inadvertently re-establishes Aang's connection to the Avatar State. Though Aang overpowers Ozai, he decides not to kill him, and instead uses the Energy Bending he learned from a Lion Turtle to strip Ozai of his bending abilities. Soon after, with his father imprisoned for war crimes, Zuko is crowned the new Fire Lord and begins to work with Aang to rebuild the three nations. The series ends as the gang meet up at Ba Sing Se while Aang and Katara kiss beneath the sunset.



Characters:

  •  Aang (voiced by Zach Tyler Eisen) is the twelve-year-old, fun-loving, Airbending protagonist of the series. Although averse to fighting, Aang is fiercely protective of his friends. He is the current incarnation of the planet's Avatar Spirit, and is therefore required to act as arbiter among the various people. According to the show's creators, the arrow-like tattoos on his forehead and arms mark Aang as an Airbending master; Aang being the youngest Airbender in history to have earned them. His mentor, Monk Gyatso, was the greatest Airbender who had ever lived, according to Aang.

  •  Sokka (voiced by All That star Jack DeSena) is a fifteen-year-old non-bender warrior of the Southern Water Tribe. With his younger sister Katara, he accompanies Aang on his quest to defeat the Fire Lord. Sokka describes himself as "meat-loving" and "sarcastic", and is often a source of comic relief. Sokka was in love with princess Yue of the Northern Water Tribe at the end of Season One and later focuses his affections back to Suki, the leader of the Kyoshi Island Warriors, in Seasons Two and Three following Yue's transformation into the Moon Spirit, though he still mourns for her. Unlike his companions, Sokka does not have any bending ability; his skill lies largely in mechanics and the sword. His chief weapons are a metallic boomerang, a blunt metal battle club, a Water Tribe machete, and later a black jian created from the metals of a meteorite.

  •  Katara (voiced by Mae Whitman) is a fourteen-year-old Waterbender of the Southern Water Tribe, the last one in that tribe. With her older brother Sokka, she accompanies Aang on his quest to defeat the Fire Lord and, eventually, becomes his Waterbending master. Katara is one of the only 2 surviving waterbenders of the Southern Water Tribe ( the other being Hama) and one of only two Waterbenders able to manipulate and control human bodies by bending the water and liquids therein, known as bloodbending (an ability used twice in the series). Katara is usually kind-hearted and generous, but is deeply hurt, hostile and often angered by the slightest betrayal and treachery.

  •  Toph Beifong (voiced by Jessie Flower), a twelve-year-old blind female Earthbending prodigy, first appears in the second season. After a vision Aang received while in a swamp, she becomes Aang's Earthbending instructor. Despite being blind, Toph "sees" by feeling vibrations in the ground through her feet using Earthbending. This ability also enables her to feel the pulses of one's heart, allowing her to tell if someone is lying. She is later shown developing a method of Metalbending by detecting earth-based impurities in the metal. She was strictly taught only the basics of Earthbending by a tutor but learned its original form from badger-moles, the original Earthbenders.

  •  Zuko (voiced by Dante Basco) is the sixteen-year-old Firebender, exiled prince of the Fire Nation, original antagonist of the first season, an antihero in the second season, and a protagonist in third season. He is determined and strong-willed, and he rarely shows compassion until the third season. He is obsessed with regaining his lost honor, only to discover its true meaning at the end of the series. During season two, Zuko struggles to deal with his anger, self-pity, and complex familial relationships as well as the choice between good and evil. He also takes on the vigilante identity of the "Blue Spirit" throughout season one and season two. In season three, he defects from the Fire Nation to join the Avatar. At the end of the series, he is crowned the new Fire Lord of the Fire Nation. In this position, he ends the war and promises to aid in rebuilding the other nations to peace and harmony.

  •  Azula (voiced by Grey DeLisle) is the princess of the Fire Nation, Zuko's younger sister and one of the primary antagonists of the series. Although she is much older in appearance, it is confirmed by the official website that she is intended to be 14, making her two years younger than her brother. Azula is a Firebending prodigy and is one of the few living Firebenders capable of casting lightning. She is a cunning master at manipulation and a great leader, using fear to control her subjects and friends alike, reserving loyalty solely for her father. She is meticulous and calculating, but also a megalomaniacal perfectionist. She is seen to be extremely capable and resourceful, bringing down the entire Earth Kingdom in her ruthless pursuit of the Avatar in season two. At the end of season three, she loses her sanity altogether due to deep rooted psychological problems and a fragile mental state broken by the betrayal of her friends, the abandonment of her father, and her elevation to a position of power. She is defeated by Zuko and Katara in an Agni Kai.


  • Momo (voiced by Dee Bradley Baker) is an intelligent and curious winged lemur discovered by Aang at the Southern Air Temple. He often picks fights with other winged and smaller creatures and with Appa over food. He is capable of understanding Aang's speech, but less so of understanding others. In "Tales of Ba Sing Se", Momo’s name was written as 模模 (mó mó). Momo means "peach" in Japanese (he grabbed a peach out of Sokka's hand just as Aang was about to name him), but it is written 桃, which also means peach in Chinese.

  •  Appa (voiced by Dee Bradley Baker) is Aang's flying bison, who serves as the protagonists' mode of transport around the world. He remains in suspended animation with Aang for one hundred years and shares a very strong bond with him. He possesses the ability to fly and can use his tail to create incredibly strong and powerful gusts of air. According to Aang, the flying bisons were the first Airbenders.

  •  Suki (Jennie Kwan) is the leader of the young and exclusively female Kyoshi Island Warriors, a sect established by Avatar Kyoshi. She is an exceptionally skilled fighter and staunch ally of the protagonists. She was imprisoned by the Fire Nation after the Kyoshi Warriors were defeated by Azula, but she was ultimately released by Sokka and Zuko. She remained with the protagonists thereafter and fought with Toph and Sokka to disable the Fire Nation's air force. She was Sokka's love interest and girlfriend immediately following the end of the War.

  •  Fire Lord Ozai (Mark Hamill) ruler of the Fire Nation, is the father of Zuko and Azula, younger brother of Iroh, and the supreme antagonist of the series. Ozai is depicted as a cruel and merciless leader, and is described as "the worst father in the history of fathers" by his son Zuko, of whom he reportedly thought banishment too light a punishment. He favors Azula over Zuko, because he sees her as a firebending prodigy and sees his own beliefs embodied in her. In "Sozin's Comet: The Final Battle", he renames himself the Phoenix King, ruler of the world, and appoints Azula to watch over the Fire Nation alone; but is defeated by Aang, who removes Ozai's ability to firebend.