Having survived the terrible battle with Azula, Aang faces new challenges as he and his brave friends secretly enter the Fire Nation.
Their quest is to find and defeat Firelord Ozai. Along the way, they discover that Ozai has plans of his own. The leader of the Fire Nation intends to use the massive power of Sozin's Comet to spread his dominion permanently across the four nations.
Short on time, Aang has a lot of bending to learn and no master to help him learn it. However, his friends are there to help, and he finds unexpected allies deep in the heart of the Fire Nation.
In the spectacular four-part conclusion, Aang must fulfill his destiny and become a fully realized Avatar, or watch the world go up in smoke.