Aang, Katara, and Sokka awake from their camp site and are startled by loud noises coming from the distance. Aang and Katara are curious and set out to investigate with a less-than-cooperative Sokka right behind. They then find a young Earthbender practicing his bending. Katara introduces herself, but before she can finish, the young bender races off, seeming very fearful. Katara decides that they should follow him, and they end up in a small town that happens to be under Fire Nation control. They later find the same young man and follow him into a store. He is talking to his mother when Katara, Aang and Sokka enter the store asking why he ran. He tells them that his name is Haru; he and his mother explain that since the Fire Nation took control of the town, any one discovered to be an Earthbender is arrested and sent to a mining rig, far off shore. Haru then tells them that his father was also sent to the rig a long time ago.

Later on that day, Haru and Katara are walking with each other, both sharing their own stories and seemingly falling for one another, when they come across an old man that has been trapped by a cave in. Haru reluctantly uses his Earthbending to save the old man. The next morning, Katara wakes up to get some water when Haru's mother tells Katara that the old man he had saved told the Fire Nation that he was an Earthbender and was arrested and sent to the mining rig. Once she learns of Haru's situation, she decides to take action and find a way onto the rig. She decides the only way to get to that rig is if the Fire Nation thinks she's an Earthbender, so after some strategy she is able to "Earthbend" with the help of Aang and some ventilation pipes while Fire Nation solders are watching. So now she's captured and sent to the rig. There she and some other captives meet the Warden of the rig, a self-important and cruel taskmaster. He states that since the entire rig is made of metal, there is nothing for the Earthbenders to control so they are helpless. After finding Haru and his father Tyro, she asks what their plan is to escape. Tyro says that escape isn't an option and that the only way to survive is to do what they're told and hope the war goes in their favor. Shocked by his lack of hope, Katara tries an inspirational speech to try to stir to life the spirits of the other benders, but to no avail. That night Katara meets up with Aang and Sokka to try to find a way for the prisoners to fight back and gain back their confidence. Then Aang notices the smokestacks and states that they are burning coal and therefore there is earth on the rig that the prisoners can use.

Drawing from her experience from the fake Earthbending she used to get herself arrested, they have Aang close all the vents around the fire save for one that will lead to the outer vent where Katara and Sokka are. Then the Warden discovers them and states that they are to surrender or die. Then the coal bursts from the vent and lands in front of Haru and the others, Katara tells them that this is their chance to stand up and fight. But no one seems to have the will to fight anymore. The Warden states that their spirits were broken a long time ago and he walks away in triumph.

Or so he thinks, as a chunk of coal strikes him on the head. He turns around to see that it was Haru who threw it. The Warden attacks Haru, but his attack is blocked by Tyro and two other benders. Then all together the prisoners attack the Fire Nation soldiers and after a dramatic fight the Earthbenders are victorious and they throw the warden overboard. They then sail off in stolen Fire Nation ships.

After winning their freedom, Tyro thanks Katara for giving his people hope again, then Haru thanks her. She is touched by Haru's words when she notices that her mother's necklace is gone. There on the rig we see Katara's necklace on the ground and is picked up by Zuko. And with a blank look he clutches the necklace and looks out toward the horizon.