The movement plans to take the people in the Fire Nation colonies and move them into the Fire Nation itself.However, an unexpected controversy breaks out, as the older colonies are composed of people who have never lived within the Fire Nation and have intermarried with Earth Kingdom citizens.These people view the movement as robbing them of their homes.
When the Earth Kingdom army arrives to enforce the Restoration Movement, Zuko deploys his own forces in defense of the colonies, leading to an explosive showdown between the recently belligerent sides and threatening to reignite the fires of war.
Aang must decide whether to follow through on his promise, and decide the fate of the colonies in the process.
In the midst of this dispute, Toph's new metal bending school finds itself in trouble, while Aang is confronted with the "Avatar Fan Movement," a growing group of young individuals trying to live as the air nomads did, but Aang views these people as parodying and denigrating the memory of his people.
Following Fire Lord Ozai's defeat and the conclusion of the Hundred Year War, the Harmony Restoration Movement is established to remove the Fire Nation Colonies in the Earth Kingdom and relocate the colonists to the Fire Nation.
Having become the new Fire Lord, Zuko makes Aang promise to kill him, should he turn out like his father.
One year later, Zuko survives an attempt on his life made by Kori Morishita, in protest against the Harmony Restoration Movement.
Learning that Kori is the daughter of the Mayor of Yu Dao, the first colony created by the Fire Nation, Zuko travels to the city to confront the Morishita family.
He learns that over the last century, the Fire Nation colonists have become deeply integrated with the original Earth Kingdom citizens, to the point that there are now mixed-race families, industries that use expertise from both cultures, and Earthbenders who consider themselves Fire Nation citizens, including Kori.
Avatar: The Last Airbender – The Promise is a graphic novel in three parts written by Gene Yang and illustrated by Studio Gurihiru, the first in a series of graphic novel trilogies serving as both a continuation of the Avatar: The Last Airbender and a prequel to The Legend of Korra, both animated television series created by Michael Dante Di Martino and Bryan Konietzko.