Episode 1: Katara and Sokka, two siblings from the Southern Water Tribe, discover a boy trapped inside an iceberg floating on the sea after Katara accidentally waterbends in a fit of rage while reprimanding Sokka. They free him and he introduces himself as Aang, an airbender of the Air Nomads—a culture believed to be extinct for 100 years. Aang and his flying six-legged sky bison, Appa, accompany Katara and Sokka to their village. Meanwhile, Prince Zuko of the Fire Nation, accompanied by his uncle Iroh, is patrolling the surrounding waters in search of the Avatar, a fabled immensely powerful bender who can bend all four elements and restore balance to the world. Katara confides in Aang that she is a waterbender, but there are no other waterbenders in the Southern Water Tribe to teach her. Aang offers to take her to the Northern Water Tribe to find a teacher. A chance encounter with an abandoned Fire Nation ship reveals that Aang is unaware of the war that the Fire Nation has waged against the other nations of the world for 100 years; Katara deduces that Aang must have been frozen for at least that long. The pair accidentally set off a signal flare on the ship, alerting Zuko, who already suspects the Avatar is nearby.
Episode 2: After bringing Fire Nation attention to the village, Aang is banished despite Katara's objections. Zuko soon descends on the village and demands the Avatar be handed over to him. Aang returns to the village to defend it, where Zuko identifies him as the Avatar. He surrenders himself to Zuko on the condition that the villagers are left alone, to which Zuko agrees. Katara and Sokka decide to pursue Aang on Appa. Aboard Zuko's ship, Aang eventually manages to break free from the guards and battles with Zuko in the process. Aang is nearly defeated, getting knocked into the water and almost drowning, but he saves himself in his "Avatar State", in which his eyes and tattoos glow and he channels an incredible display of waterbending to overpower Zuko and his crew. As the three fly away on Appa, Aang explains his reluctance towards being the Avatar, and the group sets a course for the North Pole so that he and Katara can learn waterbending.
Episode 3: Aang is eager to return to his home at the Southern Air Temple, though Katara worries that evidence of the Fire Nation's assault on it may upset him. He shows Katara and Sokka around the now-deserted temple, reminiscing about his mentor Monk Gyatso. The group find a room filled with the statues of all previous Avatars (Aang's past lives) in order of their reincarnation, the most recent being Avatar Roku of the Fire Nation. While playfully chasing a flying lemur, Aang discovers Gyatso's skeleton, surrounded by Fire Nation remains. Aang enters the Avatar State in his grief, causing the eyes of the statues at the temple and all over the world to glow brightly, alerting everyone to his existence. Once Katara and Sokka calm Aang down, he accepts that he is the last surviving Airbender. As they leave the temple, they adopt the lemur as a pet, naming him Momo. Meanwhile, Zuko stops to make repairs to his ship and is greeted by Zhao, a commander in the Fire Nation navy. Zuko tries to hide that he has seen the Avatar, but Zhao discovers the truth and takes on the task of capturing the Avatar himself, deeming Zuko a failure. Zuko refuses to accept this, as capturing the Avatar is the only way he can return from his banishment from the Fire Nation. Tensions rise between the two, with Zuko challenging Zhao to a firebending duel (known as an Agni Kai). Zuko wins the duel, but spares Zhao. Zhao then tries to attack Zuko while his back is turned but is stopped by Iroh, who intervenes and chastises Zhao for his dishonorable conduct and poor sportsmanship. The Agni Kai sparks a bitter rivalry between Zuko and Zhao.
Episode 4:Looking for a short break from their travels, Aang brings the group to the Earth Kingdom's Kyoshi Island, where he seeks to ride Elephant Koi, enormous fish who inhabit the surrounding waters. However, the group are captured by the Kyoshi Warriors, a group of warriors (consisting entirely of girls) who protect the island. The trio are freed when Aang proves he is the Avatar, a reincarnation of Avatar Kyoshi, and he quickly gains reverence among the island's inhabitants. His popularity, especially among the girls, soon goes to his head and creates a rift between him and Katara. Meanwhile, Sokka is embarrassed after being bested by girls in combat training, and strives to prove himself stronger than the Kyoshi Warriors. When he suffers further embarrassment, he swallows his pride and respectfully asks to be trained by their leader Suki, who agrees. Aang's desire for popularity soon puts himself and Katara at risk when he tries to ride an Unagi sea serpent, as well as the whole island when Zuko gets word of his location. Zuko attacks, but Aang, Katara, and Sokka all manage to escape before the entire island is decimated. Aang uses the Unagi to extinguish the fires caused by the Fire Nation attack.
Episode 5:The next stop on the group's trip is the Earth Kingdom city of Omashu. There, Aang shows Katara and Sokka the Omashu mail delivery system, a massive network of stone causeways which he and his friend Bumi (Sanskrit word for 'Earth') had once ridden for fun a hundred years previous. The trio gives the chutes a try but runs into trouble after they destroy a cabbage merchant's cart. Brought before the king of the city, an elderly and erratic man, the three are unexpectedly given a feast, during which the king outs Aang as being the Avatar. He imprisons the three and puts Aang through three deadly challenges the next day to test his skills and earn Katara and Sokka's freedom, culminating in a duel with the king himself. After Aang passes all of the challenges, the king forces Aang to guess his name. Aang ponders the question, finally deducing the king is his old friend Bumi. Bumi and Aang finally reunite, Katara and Sokka are set free, and Bumi divulges that he put Aang through the challenges as a means of preparing him for his eventual confrontation with Fire Lord Ozai.
Episode 6:Aang, Katara, and Sokka camp near a small Earth Kingdom town where they meet a young earthbender named Haru. They find the town is occupied by the Fire Nation, and earthbending is forbidden with risk of imprisonment. Katara convinces Haru to save an old man using his earthbending, only for the same man to turn Haru in to the Fire Nation. Katara devises a plan to save Haru by getting herself arrested for earthbending, which she fakes with some help from Aang and Sokka. When she arrives at the Fire Nation prison, a metal sea fortress that is impervious to earthbending, she finds Haru and his long-imprisoned father Tyro. However, she also discovers that all of the prisoners have lost hope of escape due to their inability to bend. Katara successfully leads a rebellion with Aang and Sokka's help by delivering the earthbenders coal from the fortress, which Katara uses to inspire them into action. The earthbenders escape after battling the Fire Nation guards, and return to their occupied towns with plans to rebel against Fire Nation occupation. Haru thanks Katara for reuniting him with his father, while Katara is dismayed when she realizes her late mother's necklace is missing, only to be found by Zuko back on the fortress.
Episode 7:The trio find themselves in a small Earth Kingdom village that is being attacked by Hei Bai, a monster from the Spirit World. The villagers believe that Aang can make peace with the spirit, since the Avatar is the bridge between the Physical and Spirit World. Aang unsuccessfully tries to calm the monster, which kidnaps Sokka in the process of attacking the village. Aang pursues Sokka, but fails to rescue him and ends up in the Spirit World, from which he cannot be seen or heard, nor does he have the ability to airbend. While there, he is told that the previous Avatar, Roku, has a message for him on the Winter Solstice, delivered by the spirit of Roku's dragon. After returning, Aang proceeds to calm the attacking spirit, who was upset that the nearby forest he watches over was destroyed by the Fire Nation, restoring peace to the village. Elsewhere, Iroh is captured by Earth Kingdom soldiers while bathing in a hot spring. The soldiers plan to take him to the Earth Kingdom capital, Ba Sing Se, to face justice, but Iroh proves to be an immensely formidable firebender, even when restrained. Zuko eventually catches up with the soldiers to help free him, forgoing his chase for the Avatar for a time.
Episode 8:Aang, Katara, and Sokka travel to a temple on an island in the Fire Nation, so that Aang may receive Roku's message. The three bypass a blockade led by Zhao; Zuko pursues them through the blockade, despite being banished from the Fire Nation. At the temple, they discover that the Fire Sages who guard the temple are no longer loyal to the Avatar, but to the Fire Lord. The sages attack, but one proves to still be loyal to the Avatar and leads them to the temple sanctuary. Aang manages to enter the sanctuary after narrowly avoiding capture. Zhao arrives, intending to apprehend both Aang and Zuko. Avatar Roku appears to Aang and informs him about a comet that Fire Lord Sozin used to begin the war by harnessing its power to enhance the Fire Nation's bending and wipe out the Air Nomads attempting to kill Aang. The comet will return by the end of the coming summer, and give Fire Lord Ozai the power to finish the war with a brutal assault; Aang must master all four elements and defeat the Fire Lord before the return of the comet. Roku's spirit manifests inside Aang's body, repelling Zhao's forces with a staggering display of bending that destroys the temple as Aang, Katara, Sokka, and Zuko escape.
Episode 9: Aang grows frantic over the fact that he must master all elements to defeat the Fire Lord before Sozin's Comet arrives, so Katara begins teaching Aang waterbending, despite her limited training. Waterbending comes naturally for Aang, much to Katara's frustration. Later, while in town to buy supplies, Katara finds a waterbending scroll on a ship run by pirates, which she promptly steals. Katara struggles to learn the techniques in the scroll, while Aang picks them up quickly, further frustrating Katara. Meanwhile, Zuko runs into the pirates and agrees to help them find the scroll, and subsequently Aang. They soon find and capture Aang, Katara, and Sokka, but Sokka turns the pirates against Zuko, and the three escape in the ensuing chaos, with Aang and Katara using their newly-learned waterbending skills to overwhelm their enemies.
Episode 10: After stumbling into an encampment of Fire Nation troops, Aang, Katara and Sokka are rescued by a rogue teen named Jet and his group of Freedom Fighters. Jet invites the team back to their vast treehouse hideout, where the group plots out its attacks. Jet and Katara form an instant bond, but Sokka has suspicions about him, which leads the young rebel to tempt Sokka with missions. His plan fails, however, with Sokka becoming increasingly concerned about Jet's motives and true objectives after he attacks a harmless old man simply due to him being from the Fire Nation. Sokka is unable to convince Aang and Katara to believe his concerns, while Jet enlists them to help him "save" a nearby Earth Kingdom town by filling up the reservoir. That night Sokka follows Jet and discovers his real intent is to drown the village, sacrificing the lives of innocent civilians to destroy the Fire Nation garrison stationed there, only to be captured by Jet. The next day, after filling the reservoir faster than expected, Aang and Katara learn of Jet's true plan. They try to stop it but Jet interferes. Katara manages to freeze Jet to a tree but are unable to prevent the reservoir from being destroyed, washing away the town. However, Sokka arrives, revealing he managed to evacuate the town, Earth and Fire citizens alike, with the help of the old man in time to thwart Jet's plot.
Episode 11: The group ventures into the Great Divide, the world's largest canyon. Katara and Sokka start bickering, so Aang decides to put his diplomatic skills to the test, as the Avatar is supposed to be a conciliator and promoter of peace. He successfully solves their minor disputes, but Aang's skills are soon put to a more substantial test when two Earth Kingdom tribes, the Zhang and the Gan-Jin, who have been in a feud for over a hundred years, are forced to cross the canyon together en route to Ba Sing Se. The Gan-Jin believe that their ancient leader was robbed by the ancient Zhang leader, while the Zhang believe their leader was only trying to help and was falsely imprisoned. Aang sends Appa across with the most needy people of the two tribes, and the rest are guided by an earthbender guide across the vast, dry landscape. Along the way, they are hunted down by large and dangerous native predators called canyon crawlers — resembling a cross between a spider and a crocodile. In the end, Aang is able to end the feud by lying that their stories are based on a children's ball game and that their leaders were twin brothers, and the two tribes travel together with the guide to the famous capital city of the Earth Kingdom, Ba Sing Se.
Episode 12: Sokka is hired to assist a fisherman with the group needing money. The fisherman berates Aang and angrily tells him that he "turned his back on the world". Guilt-ridden, Aang flies away and later reveals to Katara that he ran away from home after being excluded from activities with his friends and because the monks at the Southern Air Temple wanted to separate him from Gyatso to begin his Avatar training; after getting caught in a terrible storm, he inadvertently sealed himself and Appa in the iceberg after crashing into the ocean until Katara and Sokka found him. Meanwhile, after resolving a feud on Zuko's ship, Iroh tells the crew that the scar on Zuko's face was the result of a duel with his own father Ozai, who had taken offense when Zuko spoke out in a meeting opposing a plan to sacrifice Fire Nation soldiers. Zuko was subsequently banished for showing weakness by refusing to fight Ozai, and sent to capture the Avatar. When another storm hits, Sokka and the fisherman are rescued by Aang and Katara. Aang is forced to enter the Avatar State, mirroring the events that led to him being trapped in the iceberg, but this time he is able to escape with the fisherman, Appa, Katara and Sokka. Zuko also acts heroically when his ship is struck by lightning, rescuing a member of his crew who becomes trapped on the bridge; Iroh uses firebending to redirect lightning away from the ship. Zuko sees Aang flying away on Appa, but elects not to pursue them in order to bring his crew to safety.
Episode 13: Sokka suffers from an illness due to his exposure to the elements during the storm. When Katara contracts the illness as well, Aang goes to a nearby herbalist institute in hopes of finding a cure. On his way to collect the remedy (frozen wood frogs for Katara and Sokka to suck on) Aang is captured by the Yu Yan archers, commanded by the newly-promoted Admiral Zhao. However, a sword-wielding masked marauder, the "Blue Spirit", rescues Aang from Zhao's compound. The Blue Spirit is knocked unconscious during the escape, and is revealed to be Zuko! Aang saves him and offers him friendship, but flees when he is violently rebuffed. Zuko sulks back to his ship while Aang successfully cures Katara and Sokka.
Episode 14:Katara, Aang, and Sokka come across a village that relies solely on the predictions of its fortuneteller, Aunt Wu. Sokka is skeptical and refuses to believe anything she says, trying to discredit all of her predictions. Katara, on the other hand, is obsessed and keeps returning to Aunt Wu for more predictions on her love life. Aang, who has developed feelings for Katara, attempts to win her attention throughout, with no success. Eventually he attempts to fetch a rare Panda Lily flower from the lip of a nearby volcano, which is revealed to be on the verge of erupting — a direct contradiction to Aunt Wu's cloud-reading predictions. Katara and Aang use waterbending to manipulate the clouds as a warning to Aunt Wu and the villagers, and the group manages to evacuate the village before the volcano erupts. As the lava comes toward the town, Aang pushes it back with strong airbending, causing Sokka to comment that Aang is a "powerful bender". This catches Katara by surprise, as Aunt Wu had earlier predicted that she would marry a "powerful bender". The trio depart the village, with Aunt Wu reminding Aang that just as he reshaped the clouds, he has the power to shape his own destiny.
Episode 15:Sokka, Aang, and Katara find a seemingly-abandoned Water Tribe ship that belongs to their father's fleet. Camping out by the boat, Sokka and Katara are overjoyed when they are joined by Bato, an old friend of their father, and a fellow member of the Southern Water Tribe. Bato had been injured in battle and temporarily left behind by the rest of the Water Tribe soldiers while he heals. While they reminisce about the old days, Aang feels left out. A messenger arrives with a message from Katara and Sokka's father for Bato, with instructions to find him. Aang intercepts it and keeps it to himself, fearing Katara and Sokka will abandon him. He later comes clean about the message, but Sokka, furious at Aang for keeping it from them, is insistent on leaving to find his father, with Katara joining him. Meanwhile, Zuko hires a bounty hunter, June, to help him track down the Avatar, utilizing a large mammalian mount (shirshu) with a powerful sense of smell, using Katara's necklace as the scent. After Bato's comments on his loneliness after being left behind by his fellow soldiers reminds Sokka of his sorrow the day their father left, Sokka realizes that helping Aang is where he and Katara are needed the most. However, they're ambushed by Zuko and June who then uses the message scroll to track down Aang. This leads to a skirmish, with Katara and Sokka helping rescue Aang and resume their collective journey to the North Pole. Aang returns Katara's necklace to her after recovering it from Zuko during the fight.
Episode 16 :The kids travel into a Fire Nation town, which is hosting a festival of Fire Nation culture. Unfortunately, Aang's identity is discovered but a strange man, Chey, helps the gang escape. Chey tells the trio about "The Deserter", a man named Jeong Jeong who is the first man to desert the Fire Nation army and live. More importantly, he is a powerful firebending master who is not allied with the Fire Nation. Jeong Jeong initially refuses to teach Aang because he is not ready to handle the destruction fire can bring. It is only when Avatar Roku's spirit intervenes that Jeong Jeong consents to teach Aang. Aang, unfortunately, struggles with the hard discipline required for safe firebending. While trying to prove he was ready for more, he accidentally burns Katara's hands, infuriating Sokka and Jeong Jeong. However, Katara learns that she can use her waterbending to heal, but Aang nevertheless comes to regard firebending as dangerous and vows never to do it again. Meanwhile, Aang is tracked down by Zhao, revealed to be Jeong Jeong's former student. He fights Aang, but Aang uses Zhao's lack of self-control, pointed out earlier by Jeong Jeong, against him and causes Zhao to burn his own ships. Aang is burned during the fight but is healed by Katara, as Jeong Jeong disappears without a trace.
Episode 17: The gang hears a rumor that people who travel in the air reside at the Northern Air Temple, making Aang think there were some survivors of Sozin's genocide. He is disappointed to learn that the "flying" people are not true airbenders, but just people who have learned how to use gliders on the strong air currents around the temple. Aang is further saddened that the current residents have remodeled the temple extensively, often knocking through walls and ornate Air Nomad architecture to accommodate pipes which propel their rudimentary experiments with steam pressure. Teo, a young paraplegic, inspires Aang to open the one remaining area of the temple left untouched, the Air Temple sanctuary. Aang is shocked to see the "pristine" room is in fact stocked with dozens of inventions with Fire Nation insignias on them. Teo's father, a skilled mechanist, confesses to aiding the Fire Nation by building weapons in exchange for the guaranteed safety of his son and his people. When the Fire Nation comes to collect their latest invention, Aang tells them to leave. The Fire Nation launches an attack against the temple, but Aang and the villagers manage to successfully defend their ground. The Fire Nation, however, does manage to recover the mechanist's newest invention, a war balloon.
Episode 18: The group finally reaches the Northern Water Tribe, where they receive a hero's welcome. Sokka meets Princess Yue, the daughter of the chief of the tribe Arnook, and is immediately attracted to her. Aang and Katara seek to learn waterbending from a snippy master named Pakku, but he refuses to teach Katara, as women in the Northern Water Tribe are only trained to use their waterbending for healing, with combat training reserved for men. Sokka tries to spend more time with Princess Yue, who agrees to meet him later on that night. However, when the time comes Yue changes her mind and runs away. Meanwhile, Zhao commandeers Zuko's crew for a mission to attack the North Pole, and in the process deduces that Zuko is the Blue Spirit who freed the Avatar after recognizing Zuko's broadswords. Katara, inspired by a comment from Sokka, suggests that Aang teach her what he learns from Master Pakku every night. Pakku discovers them, and refuses to teach Aang any further. In front of the tribe council, a fed up Katara refuses to apologize to Pakku so he may change his mind and instead challenges him to a duel, demonstrating her considerable skill and potential. Zhao hires the pirates from "The Waterbending Scroll" to kill Zuko, which they attempt by blowing up his docked ship while Iroh is out for a walk. Back at the Fire Nation port, Zhao feigns remorse to Iroh and offers the former general a place beside him for the mission. Iroh accepts, but is revealed to be deceiving Zhao by helping Zuko fake his own death and stow away as a soldier aboard the command ship. Back at the North Pole, Pakku takes notice of Katara's pendant, given to her by her mother and her grandmother before her, and realizes that Katara's Gran-Gran is his ex-fiancée Kanna, who also could not tolerate the Northern Water Tribe's customs and left to start a new life with the Southern Tribe. Sokka proceeds to tell Yue how he feels about her, which culminates in Yue kissing him. She sadly tells Sokka that she also has feelings for him, but they can't be together since Yue is engaged to be married. As a new day dawns, Pakku has agreed to train both Aang and Katara while Zhao's massive armada departs for the North Pole.
Episode 19:Some time later Katara has developed into Master Pakku's star pupil, earning her his highest praises. Sokka and Yue spend more time together including a ride on Appa, during which Sokka notices a storm of "soot", a tell-tale sign of an impending Fire Navy raid. As the tribe prepares for battle, the chief asks for volunteers for a dangerous mission, to which Sokka immediately agrees. As Zhao's armada closes in, Iroh meets with Zuko in disguise as a Fire Nation guard, as he tells Iroh that he's working on a plan of his own. As the Northern tribe takes up battle stations, the raid begins. Aang and Appa work to help disable the lead ship, but are overwhelmed at the size of the fleet that follows. In preparation for the chief's secret mission of infiltrating the Fire Navy, Sokka clashes with a Northern soldier named Hahn before realizing he is Yue's fiancé. Arnook takes Sokka off the mission and assigns him to protect Yue. As nightfall nears, Iroh warns Zhao to halt the attack as the waterbenders will draw power from the nearly-full moon. Zhao cryptically notes he is working on a solution, but agrees with Iroh for the interim. Iroh then meets up with Zuko, who plans to kayak from Zhao's ship and infiltrate the North Pole to capture Aang. He nearly drowns after choosing to free swim under the glacier to find a way in, but is able to infiltrate the city. Meanwhile, Aang and Katara are brought to a spiritual oasis at the top of the city by Yue, with Aang hoping to find the Moon and Ocean spirits for help. Aang begins to meditate in front of a koi pond with two fish circling each other, and when he realizes they resemble Yin and Yang he crosses into the spirit world. Zuko arrives shortly after and battles with Katara until sunrise, when he overpowers her and escapes with Aang's body as the Fire Nation resumes the attack.
Episode 20: Zuko struggles to find shelter for himself and Aang in the frozen tundra, while Sokka, Katara and Yue search for them, as the Fire Nation forces assault the city. In the spirit world, Roku contacts Aang and tells him that the ocean and moon spirits crossed over to the mortal world long ago, and that only one spirit is old enough to remember: Koh the Face-Stealer. Aang must show no emotion or expression at all when meeting with him, or else his face will be stolen off of his head. Back in the physical world, Zhao informs Iroh of his overall plan: While serving in the Earth Kingdom as a young lieutenant, Zhao discovered a secret underground library that gave him the identity of the moon spirit's mortal form, with Zhao viewing it as his destiny to kill it. Aang learns from Koh that the spirits' names are Tui and La, "Push and pull", and that they are in great danger. Aang figures out the Koi fish are the spirits, and quickly heads back to the physical world, coincidentally leading Katara, Sokka, and Yue right to his body. Zuko is quickly defeated, but Aang chooses to save him. As they fly back, Zhao captures Tui, the moon spirit, causing a lunar eclipse and the waterbenders to lose their bending. Aang and Iroh both warn Zhao that the entire world depends on the balance of the moon and ocean, including the Fire Nation. Zhao initially relents, but then attacks in a fit of rage, killing the spirit and darkening the moon completely. Iroh furiously attacks Zhao and his guards, as Zhao quickly flees. Aang enters the Avatar State and, merging with the ocean spirit, decimates the Fire Nation armada by forming a massive spiritual projection. Zuko fights Zhao in retaliation for the assassination attempt, while Iroh remains to try and revive the moon spirit. Iroh recognizes that Yue was touched by the moon spirit as a baby, by her snow-white hair. Yue confirms this as the moon spirit saved her life when she was born ill. Yue gives back the spark of life, sacrificing herself to save the Moon Spirit. She assumes the form of the moon spirit and gives Sokka a final kiss goodbye. Zhao is dragged underwater to his demise by the ocean spirit in retaliation for slaying the moon spirit, arrogantly refusing to accept Zuko's help. Pakku anoints Katara as Aang's new waterbending master as the group contemplates their next move, while Ozai assigns Zuko's younger sister to hunt down her uncle and older brother for their actions at the North Pole.
