A century has passed since the Fire Nation declared war on the other three nations of Air, Water and Earth in their attempt to conquer the world. Sokka and his sister Katara, who belong to the Southern Water Tribe, discover an unusual iceberg. Breaking into the iceberg releases a beam of light and reveals a 12-year-old boy named Aang and his flying pet bison named Appa.
Zuko, the disgraced prince of the Fire Nation, detects the light from Aang’s release and arrives at the Southern Water Tribe to demand the villagers hand over “The Avatar”: the only person capable of manipulating, or “bending”, all four elements of air, water, earth and fire. Aang surrenders himself to save the village, but escapes the Fire Nation ship and flies to Appa, brought by Katara and Sokka. The trio travel to the Southern Air Temple, where Aang learns he was in the iceberg for a century and that the Fire Nation wiped out the Air Nomads, including his guardian Monk Gyatso. In despair, Aang enters the Avatar State and finds himself in the Spirit World where he encounters a Dragon Spirit. Katara’s pleas bring Aang out of the Avatar State.
Aang’s group of companions arrive at an Earth Kingdom village controlled by the Fire Nation. When they are arrested and imprisoned, they incite a rebellion, battling and defeating the Fire Nation soldiers occupying the village. Aang tells Katara and Sokka that he only knows airbending and has yet to master the other three elements. They make their way to the Northern Water Tribe where Aang can learn from water-bending masters.