What does it mean to be the last of your kind, and what would you do to change it?

Years after saving the world, Avatar Aang and his friends are living legends. They have all followed separate paths since the Hundred Year War, and each has grown into adulthood while shaping humanity in unique ways. Though his companions look eagerly toward the future, Avatar Aang struggles to do the same. Instead, he finds himself drawn to the past, making long journeys to the abandoned Air Temples to collect what is left of his culture in a world that has already begun to move on.

When a group of violent non-benders attack the Avatar at the Southern Air Temple and steal a mysterious relic, they set in motion a race across the world for a legendary power that threatens to destabilize the fragile balance Aang worked so hard to achieve. And so Aang reassembles his team: Sokka, now an ingenious inventor helping to rebuild his home in the Southern Water Tribe; Toph, who teaches metalbending to a new generation; Zuko, whose leadership has steered the Fire Nation to an era of peace; and Katara, a leader in the young multicultural metropolis of Republic City. Together, the group traverses the globe to sites that have been abandoned for millennia, where they learn of ancient Avatars, meet powerful spirits, and uncover dangerous new abilities, one of which could grant Avatar Aang's deepest wish: to save the Air Nomad culture from extinction.

Though his team's collective hopes are great, Aang must confront whether his lifelong dream might become the very thing that destroys him-and the new world he has built.