The book begins with the usual narration that started at the beginning of every episode of Avatar. However, Katara adds a part at the end that discusses how Aang was able to beat Ozai and that Zuko became the new Fire Lord. In the days after the end of the Hundred Years War, Zuko and Aang bring back King Kuei to his palace in the Earth Kingdom to rule over it once more. They look over a map, realizing how many Fire Nation colonies are in the Earth Kingdom as Zuko vows to make things right in a plan Sokka and Kuei deem the Harmony Restoration Movement. The group relaxes some as Katara and Aang kiss, professing their love as Sokka overreacts. As they ride Appa to watch celebratory fire works, Zuko looks troubled as he asks Aang to make him a promise: if he ever turns into the man his father was, he will kill him. Aang reluctantly promises this to Zuko.
A year later, the Movement is going according to plan as Zuko awakens one night, sensing someone is nearby. Alerting his guards, they detect nothing as Zuko is able to stop an assassin from taking his life. The female assassin deems Zuko as a traitor to his people as she reveals she is from Yu Dao, the first Fire Nation colony Sozin formed nearly a hundred years ago. He takes Kori, the assassin, back to her home as her father is Mayor Morishita. Zuko explains what happened as Morishita claims that Zuko is doing no one in the city justice as his father was a better man than he. He has a flashback to the last time he saw Ozai in prison, demanding to know where his mother is. Ozai laughs it off, telling Zuko to bring him tea and they'll talk. He chides his son, noting that being the Fire Lord is a challenging task and that he doesn't have it in him. Zuko attacks Morishita as he states that he is a coward and a traitor.
Elsewhere, Aang, Sokka, and Katara are helping to relocate colonials as a part of the Harmony Restoration Movement. Aang comforts the younger colonials as he promises all will be well. However, when they land in the Fire Nation, a group of guards tell them that they need to go back as Zuko has renounced the Harmony Restoration Movement: an announcement that shocks them all. Meanwhile, Toph is breaking down hard on her students in the Bei Fong Metalbending Academy, trying to get her only three students to learn the art by imploring similar methods she used with Aang. They realize that there is a commotion down the mountain as that is where Yu Dao is located. Toph wonders what is going on as she hears Appa in the sky. Launching herself up, she greets Katara and Sokka as Aang is meditating. Meeting Avatar Roku's spirit, Roku apologizes for the mess he made as Aang doesn't want to kill Zuko. Roku agrees with Zuko, knowing that if he did the same with Sozin, they would not be in this mess. Aang vows to try and resolve this peacefully first.
At the gates of Yu Dao, a protest movement by the Freedom Fighters has formed, lead by Smellerbee and Longshot. Smellerbee wants to use violence but Aang declares he and Katara will hop the city wall to talk to Zuko. Once over, the Fire Nation guards tell them to leave before attacking. Aang is able to fend them off but his clothes catch fire quickly. Katara aids him as she uses her ice attacks before being stopped by Zuko. Aang is convinced that he has to keep his promise, entering the Avatar state as Katara calms him down. Zuko tries to explain as Aang yells at him. Zuko takes him around the city, telling them that Yu Dao is the oldest colony of the Fire Nation and that Earth Kingdom citizens and Fire Nation colonists have learned to get along despite there being a few class issues. They wonder what changed his mind as he relates how when he confronted Morishita, he found his wife to be an earthbender as well as Kori too, but pledge loyalty to the Fire Nation. Zuko agrees to leave Yu Dao alone as Aang states that peace comes from four seperate nations, not an amalgamation as Katara agrees with Zuko. Not sure what to do, they agree to hold a summit in Yu Dao to think things through.
Outside, Sokka and Toph are trying to control the crowd as someone attacks Sokka. Toph, angered, pushes back as Aang and Katara return. Aang announces the summit as Smellerbee is impatient, giving them three days to fix it their way or else. As they ride off, they explain how there are a lot of issues to consider as Aang thanks Katara for her support. At the Fire Capital, Zuko laments what has happened as Mai tries to comfort him. Knowing he hasn't slept in a week from his problems, she elicits the help of the Kyoshi Warriors as Suki and Ty Lee become his personal guards. Still unable to sleep, Zuko awakens in the middle of the night as he claims he is going for a walk. In reality, he brings tea to his father in prison, confessing he needs help.