A devastating war has raged for 100 years, with the Fire Nation bent on conquering and ruling all the other nations for eternity. At the South Pole, a young Water Tribe girl and her brother make an amazing discovery: a 12-year-old boy enclosed alive in ice for 100 years, the last survivor of the annihilated Air Nation. He is the long-lost Avatar. But can he fulfill his destiny in time to save the world?