After spending a century frozen in an iceberg, 12-year-old Airbender Aang is discovered by Katara and Sokka, a brother and sister from the Southern Water Tribe. As the long-missing Avatar, Aang must learn to master the four elements and help bring balance to a world at war with the Fire Nation. Together, the three set out for the North Pole to find a master waterbender and begin his training.