Seeking to redeem himself for his failure during the invasion, Sokka learns from Zuko about the Boiling Rock, a top security Fire Nation prison. The two infiltrate it, in hopes of rescuing Sokka and Katara's father, Hakoda. After instead discovering Suki is imprisoned there, Sokka and Zuko hatch a plan for the three of them to escape. Chit Sang, another prisoner, overhears the plan and joins their escape efforts. As they are nearing escape, a new batch of prisoners arrives. Sokka, Zuko, and Suki decide to postpone escaping to save Hakoda, one of the new prisoners. Chit Sang and two other prisoners try to escape alone, but their plan is revealed.
Zuko serves freshly brewed tea to his new friends as they all hide out from the Fire Nation in the Western Air Temple. He tries to tell them all a tea joke his uncle once told him, but no one finds it funny as Zuko could only remember the punch-line.
As he is serving tea, Sokka asks to talk to Zuko alone. He asks where Zuko thinks Fire Nation criminals and war prisoners would be imprisoned. Zuko refuses to tell, on the grounds that knowing will only make Sokka feel worse than he already does, until Sokka states that he is concerned for what happened to Hakoda after the failed invasion. Hesitantly, Zuko answers that Hakoda would most likely be in a prison out in the middle of a volcano in the middle of the ocean, over which they had passed on Appa going to the Western Air Temple. He states that the prison is called the Boiling Rock. Zuko is suspicious of why Sokka would ask such a thing so randomly, but the latter promises him he is not planning anything.
Assuming everyone else to be asleep, Sokka tries to sneak out on Appa in the middle of the night. As he climbs onto the saddle, he finds Zuko waiting, and the firebender berates him for such a poorly thought-out plan of infiltrating the Boiling Rock prison on Appa. Sokka explains to Zuko that the invasion plan was his idea, and it failed, causing his father and many others to be captured and jailed by the Fire Nation. He informs the young prince that he intends to infiltrate the prison in which his father is held and rescue him, and to Sokka's surprise, Zuko decides to go along with him. Instead of using Appa, he suggests they use the war balloon that he stole to escape from the Fire Nation capital. The next morning, the gang finds a note written by Zuko, stating that he and Sokka had gone fishing together and reminding Aang to continue his firebending practice, much to the Avatar's annoyance.
Flying in the war balloon, Sokka and Zuko sit in awkward silence. Sokka tries to break the ice, first by commenting on the "fluffy clouds," then by whistling. Eventually, they talk about girls. Zuko misses his ex-girlfriend Mai, whom he left behind in the Fire Nation. Sokka says his first girlfriend turned into the moon. Zuko replies by saying, "That's rough, buddy."
Later that evening, they spot the prison below and descend in the balloon toward it. Large clouds of steam emit from the boiling volcanic lake surrounding the prison. Because the steam makes the air outside the balloon warmer than the air inside it, the balloon crash-lands on the beach outside the prison walls. Sokka dumps the remains of the balloon into the boiling lake so it will not be found. Zuko believes Sokka does not have any real concrete plan, and that they would be in serious trouble if they get caught, but the warrior assures him he will think of something so they can get off the Boiling Rock safely. They infiltrate the prison unnoticed and steal Fire Nation prison guard uniforms and helmets.
Impersonating guards, they are ordered to oversee a quarrel. Chit Sang, a firebender prisoner, is being harassed by a guard for not bowing down to him. Chit Sang declares bowing to the guards is not a real rule and walks off. The guard makes a whip of fire and lashes out as his back is turned, and Chit Sang firebends to defend himself. Firebending is prohibited for prisoners in the prison, and Chit Sang is sentenced to "the cooler" as punishment. A cooler is a small, insulated cell kept very cold which prisoners are locked inside as punishment. The guard forces Sokka to come with him to put Chit Sang in the cooler, leaving Zuko in the prison yard.
At lunch break for the guards, Zuko asks other guards where dangerous criminals such as prisoners of war are confined. Zuko and Sokka meet up later on and Zuko tells Sokka that Water Tribe prisoners are not located in this prison. Sokka believes he has failed yet again, but Zuko tries to cheer him up by imitating Iroh's wise sayings. Sokka does cheer up, not from Zuko's attempt, but at the sight of Suki, who is returning to her prison cell.
Sokka locates Suki's cell and enters while wearing his helmet. He attempts to kiss her, but believing he is a Fire Nation guard, she pushes him down, knocking his helmet off in the process. Upon realizing it is Sokka, Suki, overwhelmed with happiness, is driven to tears of joy. She reveals to Sokka that she knew that he would come, contrary to Azula's claim that she had given up on him, and the two kiss. Zuko spots a guard coming and warns Sokka with some knocks on the door of the cell. Zuko tries to keep the guard out, first with an excuse, before trying physical force. When Sokka comes out, back in his guard disguise, he helps the guard arrest Zuko to prevent suspicion, but whispers to him that he will figure something out, so Zuko allows himself to get captured. Zuko is interrogated by the prison's warden, who knows Zuko because the warden is Mai's uncle. The warden states that Zuko had broken Mai's heart after Zuko left the Fire Nation, and that he intends to turn him in to his father and collect the reward.
Later, Zuko and Suki are doing mopping duty together in the prison, and Suki agitatedly recognizes him as the person who almost burned down her village. Zuko awkwardly apologizes and tells her, "It's nice to see you again," and moves away. Sokka, still disguised, gathers the both of them for a plan, which Chit Sang overhears and invites himself in as well. They plan to use a cooler to ride their way out like a boat. First, someone will need to unscrew a cooler cell free. Zuko volunteers by pretending to mop and bump into Chit Sang. The two fight and Zuko firebends. After that, he is sent to a cooler cell, and having used his breath of fire technique to keep warm, is successful in unscrewing the cooler free. However, as guards pass by, Zuko and Sokka hide, overhearing that war prisoners are coming the next day; Sokka thinks there is a chance his father is among them.
That night, they bring the loose cooler cell, and Chit Sang brings two of his accomplices along to escape. Sokka, knowing about the arrival of new prisoners tomorrow, decides against escaping and stays at the prison to break his father out. Suki and Zuko agree to stay while Chit Sang leaves with his friends. At dawn, Chit Sang and his friends are sweating in the cell-boat, so Chit Sang breaks a piece of metal to use as an oar. He is burned by the steaming water and yells out in pain. The Fire Nation guards are now aware of an escape attempt and catch the cooler cell drifting away. Meanwhile, Sokka, Suki, and Zuko hide and see the prisoners come out of the lift used to transport prisoners into the prison. After a few come out, Sokka loses hope of seeing his father, until one last person is called out: Hakoda.
If you look closely at the last of the prisoners exiting the gondola, the one before Hakoda, you will see one of the pirates in "The Waterbending Scroll" and "The Waterbending Master". This was also referenced when two guards were discussing the new prisoners while Sokka and Zuko were in the cooler.
Zuko saying that Iroh once said that he never thinks things through is a reference to "Lake Laogai".
When Zuko is passing out tea and tells his joke, he only gives tea to The Duke and Haru. An aerial view is shown of the whole group around the fire. Katara and Aang seem to be holding a cup of tea but in the next frame, a close-up of Zuko, Aang and Katara, her hands are empty.
When Katara is shown sleeping, the glove portion of her armband is missing.
When Sokka is picking up the supplies he dropped after being startled by Zuko, the holes on Appa's saddle are colored solid like the rest of the saddle.
When Sokka and Zuko are told about the "scuffle in the yard", several dozen guards are seen running to the scene. However, once outside, only about one dozen guards are there.
When Zuko informs Sokka that his father is not there, his hair is tucked into his helmet. In the next frame, his hair is out. When Sokka says, "Maybe we haven't failed after all", his hair is back in his helmet.
When Sokka was explaining the escape plan, Suki and Zuko's mops were leaning against the stairway behind them, but when Chit Sang jumped down and said he wanted in, both mops were gone.
When Sokka and Zuko were rolling the cooler down the hill, the cooler door was closed, but when they stopped at the bottom of the hill, the door was already open.
When Sokka lifted the rock hiding his stuff, his sword was not there, but in the next frame he picked up his sword from behind the same rock.
The design of this prison is a reference to Alcatraz Island, a real-world island prison, which was nicknamed "The Rock". As with the Boiling Rock, Alcatraz boasted a history of no successful escapes.
It is ironic that the Boiling Rock is inescapable because of the boiling water, as the water in the San Francisco Bay surrounding Alcatraz Island is very cold, making it equally inescapable.
The warden is voiced by American actor Wade Williams, who had a starring role as Captain Brad Bellick on Fox's television series Prison Break, about a man jailed for a crime he did not commit.
"The Cooler" is the name of the isolation cells used in the prisoner of war camp in the film The Great Escape.
When Sokka was disguised as a guard, upon entering Suki's room, he was not recognized by Suki. Her lack of recognition prompted Sokka to say "Oh, you don't recognize me? Maybe you'll recognize this." This is a variant of what Suki said to Sokka when Sokka did not recognize her as a security guard whilst she was working at Full Moon Bay.
When Sokka enters Suki's cell, the scene is reminiscent of Star Wars IV: A New Hope, "Aren't you a little short for a stormtrooper?"
When Zuko discovers Sokka about to leave on Appa, there is a subtle role reversal. Zuko says that he is never happy, a line which strongly echoes one of Katara's in "The Waterbending Master" in regards to Sokka never being happy. Moments later Sokka says he has to regain his honor, a recurring theme of Zuko's during the first two books.
During the first escape plan, Sokka mentions a blind spot between two guard towers, resembling Hilt's (Steve McQueen) escape strategy by cutting through the barbed wire fence in a blind spot between guard towers in The Great Escape.
Just after Zuko is caught firebending, the scene cuts to shot of Sokka with Suki behind him. After Sokka moves off screen, there is a man standing in the background whose mouth and head movements, as he moves away, are animated almost identically to those of Sokka.
This is the first episode since Toph's feet were burned in "The Western Air Temple" that we see her walking again.
According to the "Avatar Extras" from this episode, the effects of the cooler cause most firebenders to lose their bending for about a week. Zuko has to be a very powerful firebender in order for the cooler to have no such effects on him, even with his breath of fire technique.
If Toph did not sense Sokka fall off Appa, then this implies she needs to have her feet or hands touching the ground to be able to feel vibrations, as neither were at the time.