In the "Avatar" world, there are people who are able to control, or "bend", the four elements: "Air", "Water", "Earth", and "Fire". Along with the four elements, there are four nations that correspond with each element. Not everyone can bend an element, and those that can are only able to bend one. However, The Avatar is able to control all four elements as well as communicate with the spirits. The Avatar is also born into one nation, and after dying, is reincarnated into another nation following the pattern of Air, Water, Earth, Fire. The series takes place 100 years after the Fire nation started a war against all other nations and has killed off all air benders in search of finding the avatar who has been reincarnated as an air bender, Aang. The avatar, trapped in ice for 100 years knows nothing of the war. The series starts with Aang being accidentally freed by Katara and Sokka. The series then primarily follows the adventures of Aang and his companions, Sokka, Katara, and later Toph, as he tries to master all four elements and defeat the fire nation. There is also a strong secondary focus on Zuko, banished and disinherited crown prince of the . Zuko was burned by his own father, the Fire Lord Ozai. Zuko then tries to capture Aang in order to regain his peerage and honor, but in the end he help Aang to master the fire.