Avatar is the story of Aang, a boy who has the ability to bend air, water, earth, and fire, known as the avatar. When two water-tribe teenagers, Sokka and Katara, find him trapped in ice, they free him and tell him that his people, the air nomads, are extincted. Then, Aang finds out there is a war between the water tribe, the fire nation, and the earth kingdom and it is his duty to stop the war, and keep the fire lord, Ozi, from taking over the world.
And, thats Avatar in a nutshell, or season 1 at least. The series is over, but you can watch it online.
edit: Aang was trapped in the ice for 100 years.
