After accidentally revealing his status as the Avatar at a festival, Aang is brought to Jeong Jeong, a firebending master who rejected the Fire Nation. Jeong Jeong initially refuses to teach Aang firebending, but concedes after Avatar Roku appears to him in a vision. During his instruction, Aang accidentally burns Katara; although she is able to cure herself through her newly-discovered healing abilities, Aang vows to never firebend again. Soon after, Zhao locates and attacks them. Aang remembers Jeong Jeong's teaching about the importance of self-restraint, and upon realizing Zhao lacks this trait, he manipulates Zhao into destroying his own fleet.
While venturing through the northwesternEarth Kingdom, Aang and his friends decide to attend a "Fire Days" festival in a Fire Nationtown where Aang can witness firebending firsthand. However, Sokka points out they are wanted criminals. To ensure they are not discovered, they disguise themselves and acquire festival masks soon after their arrival. At first, the three enjoy the festivities, although they bear witness to a puppet show where Fire LordOzai is presented as a great hero, facing off against "evil" Earth Kingdom soldiers. They stumble upon a firebending show, which has the audience dazzled. When asking for volunteers for his next trick, the performer, Malu, calls Katara up to the stage he has her play the part of a damsel in distress and ties her to a chair. Malu then creates a dragon of fire; making a show of it, however, he seems to lose control of it, and it flies directly toward Katara. Aang, fearing for Katara's safety, leaps onto the stage to shield Katara, and uses airbending to stop the fire dragon. It is revealed to the crowd that Aang is the Avatar, causing Fire Nation soldiers to give chase to him, and the three friends quickly attempt to escape from them.
Their escape is aided greatly by a man named Chey; he explains that he serves a firebending master named Jeong Jeong, who has abandoned the Fire Nation. He says that Jeong Jeong was the first to leave the Fire Nation Army and live, while he himself is the second. He admits, however, that being the second does not make him famous. Chey leads the trio to Jeong Jeong's camp within a forest, but they are intercepted by Jeong Jeong's followers, led by Lin Yee. Chey greets them as friends, though the followers are indifferent. They arrive at the camp, where Aang attempts to persuade Jeong Jeong to instruct him. Meanwhile, back at the town, AdmiralZhao arrives and, upon learning Aang and his team passed through, decides to pursue them himself. He orders his men to prepare river boats to search the woods into which Aang fled earlier.
Back at Jeong Jeong's hut, the firebending master refuses to even see Aang. Regardless, Aang barges into Jeong Jeong's hut to try to persuade the master to teach him firebending. Jeong Jeong retorts that Aang must first master waterbending and earthbending, going on to say that water is "cool and soothing", earth is "steady and stable", but fire "will spread and destroy everything in its path", so Aang is not ready to learn the art yet. However, in the middle of his lecture, a vision of Avatar Roku appears to Jeong Jeong; the vision instructs him to teach Aang firebending, and he begrudgingly agrees to obey the order.
Jeong Jeong begins by teaching Aang the basics, focusing exclusively on breathing exercises, but the young Avatar desires to learn more advanced firebending techniques. After spending hours on end working on squats, performing breathing practices, and feeling the sun's energy, Aang grows impatient and accuses Jeong Jeong of wasting his time. Jeong Jeong is greatly angered with Aang's lack of discipline, telling him vehemently that without control, firebending will bring nothing but unnecessary destruction, using a former student of his who displayed similar impatience and lack of discipline as an example. Aang quickly apologizes and says that he is ready to learn Jeong Jeong's way.
Jeong Jeong proceeds to instruct Aang in actual firebending, much to Aang's enthusiasm. However, his eagerness quickly fades when Jeong Jeong only assigns him the simple task of preventing a leaf from being completely burned. Jeong Jeong leaves to take care of other matters, and Aang, still feeling restricted, takes his exercise to the next level and creates fire. Aang plays around with it for a little while, with Katara insisting that he be careful. Ignoring her pleas, he continues to firebend and accidentally burns Katara's hands when he attempts to imitate a move the performer executed at the festival. Katara cries in pain and runs away while Sokka angrily tackles Aang.
Katara tries to cool her hands from the burn in water and, after a few seconds, miraculously heals herself despite being inexperienced at healing. Jeong Jeong tells Katara that she possesses vitakinetic healing powers, with water as the catalyst. Jeong Jeong confesses his desire to be a waterbender like her, due to its ability to heal, explaining that fire only destroys. However, during this time, Admiral Zhao, who is revealed to be the former student of Jeong Jeong mentioned earlier, and his men locate the camp and, in turn, battle Jeong Jeong, although the master's attempt is half-hearted.
Aang, hiding away in Jeong Jeong's hut in order to reflect over his error, is urged by Katara to aid Jeong Jeong. Although Aang feels terribly guilty and promises to never firebend again, Katara's revelation of her healing restores his battle spirit. With a fiery display, Jeong Jeong and his men make their escape into the woods, while Aang confronts Zhao. Recalling Jeong Jeong's lesson of control, Aang provokes the admiral, goading him into destroying his own ships. The enraged Zhao watches his ships burn as Aang escapes.
With Jeong Jeong gone, the three resume their journey and leave the forest, a hard-learned lesson of fire's destructive power fresh in their minds. Meanwhile, Chey returns to the campsite, only to find it deserted.
While riding on Appa, Katara notices Aang had burned his arm while fighting Zhao. She demonstrates her new ability by healing the injury. When Katara tells them that she must have always possessed her healing abilities, Sokka rants about the many times in the past when Katara failed to use her abilities to aid him.
This is the first episode where Aang firebends. He keeps true to his promise to abstain from firebending until "The Firebending Masters", where he finally becomes comfortable with the art.
Jeong Jeong is spoken about in "The Western Air Temple" when the group discusses the chances of finding a firebender willing to teach Aang. Aang says they will never see Jeong Jeong again; however, Jeong Jeong is seen again in "Sozin's Comet, Part 2: The Old Masters", although Aang was not with the group at the time.
All four wanted posters seen at the beginning of the episode are later seen in "The Desert", along with new ones for Iroh and Zuko.
This episode reveals that waterbenders have healing capabilities, and is the first episode in which Katara uses this ability.
When at the Fire Festival, Katara, though wearing a mask, is still wearing her Water Tribe necklace, which if noticed, could have gotten them captured.
When Katara switches Aang and Sokka's masks at the festival, her necklace disappears. Throughout the festival, her necklace disappears and reappears multiple times.
The firebending magician's clothes change several times during his scene.
During the Taming the Dragon part of Malu's act, the wall behind Katara is perfectly intact, but when the gang runs away, the wall is partially destroyed, without any damage having been inflicted to it.
As Aang performs breathing exercises on the mountain, Jeong Jeong begins walking down the mountain. Right before he completely disappears, the rest of his visible hair completely vanishes.
As Aang confronts Jeong Jeong about wasting time, Jeong Jeong's scars go over his eyebrows. However, as Jeong Jeong talks, the position of the eyebrows move but the scars do not, as if the scars were not there. This happens several times throughout the episode.
An outline of Zhao's figure should have been seen through Jeong Jeong's wall of fire before he steps through the flames, but it is not.
Aang is covered in mud as he hops on Appa after the battle with Zhao, but he is completely clean in the next shot, save for a small patch of mud on his left shoulder.
No burn marks inflicted by Zhao are visible on Aang during the battle, but when he gets out of the water after jumping off Zhao's boat, several can suddenly be seen.
When Sokka argues that they should not go see Jeong Jeong, Katara says, "It wouldn't hurt to at least talk to him." Ironically, Katara later gets hurt because of the firebending Aang learned from Jeong Jeong.
When Aang saves Katara from the firebending magician, he uses the same move that the shadowed airbender in the opening sequence uses.
This is the only episode where Zhao appears but Zuko does not.
This is the only known time when an Avatar has broken the order in which the elements are mastered.