When Aang and his friends find a professor who knows of a library that contains information about the world, Sokka decides to go there to hopefully find some information to use against the Fire Nation. The library is guarded by the knowledge spirit, Wan Shi Tong, who doesn't welcome humans into his library, because he believes they only seek information for evil purposes. When Wan Shi Tong discovers Sokka wasn't being truthful with him, he begins to sink the library, bringing the kids down with it.

Toph's instructing abilities come into question when Aang cannot seem to overcome a block that keeps him from earthbending. Sokka gets himself in a jam, while befriending what was, moments before, his next meal, and Iroh and Zuko begin training utilizing new philosophies and methods that originate from the other elements.

Tired from trying to escape a machine that shows up every time they try to sleep, Aang and the gang have to escape Azula and her team, but their exhaustion leads to a tight situation. Meanwhile, Zuko must deal with something personal, and Iroh bonds with an unlikely individual.

Zuko travels by himself to an Earth Kingdom town were he meets a local boy. The two almost become friends, while Zuko suffers from flashbacks of his past.

In search for an Earthbending teacher for Aang, the kids go to an underground Earthbending tournament called Earth Rumble 6, where they encounter Toph, a blind but powerful Earthbending girl. After seeing her unique style of Earthbending, Aang wants Toph to become his teacher, but there are complications with Toph's family.

Aang and the gang discover an Earth town that celebrates something called "Avatar Day." But when they get there and learn the festival is of "anti-Avatar" sentiment and Aang is put on trial for a crime a past incarnation allegedly committed. Looking to clear the Avatar's good name, Katara and Sokka venture back to a familiar place to gather evidence and discover the truth.