After 100 years, the Avatar-spiritual master of the elements-has returned. The Four Nations (Water, Earth, Fire, and Air) have become unbalanced. The Fire Nation wants to rule the world, and its first conquest will be the Northern Water Tribe. It's up to a 12-year-old Airbender named Aang to find a way to stop it. Join Aang, Katara, Sokka, Momo, and Appa as they head north on the adventure of a lifetime.