Aang continues his journey to defeat Chu Zun and the Fifth Nation, but he is unprepared for his greatest battle yet: the battle within. Zuko recovers from the fight with Jinshu, Iroh's past is revealed, and Azula will be forced to make a choice. This is a sequel to "Avatar: The Five Nations - Book 1: Metal".

Three years after the events of Avatar: The Last Airbender, a new threat from Aang's past rises. Meanwhile, Zuko faces the consequences of his family's actions, and Toph continues her pursuit to teach metalbending. This is the first part of a planned trilogy.