Of all the couples in Nickelodeon's Avatar: The Last Airbender, Aang and Katara are one of the most beloved by fans. With a narrative arc stretching from the first moments of the pilot to the final seconds of the finale, their deep friendship and eventual love for each other not only impacts their personal lives, but also the entire trajectory of the war and the fates of the four nations.
Although their relationship is almost always healthy and mutually fulfilling, there are times across the show's three seasons where Aang and Katara struggle with communication, honesty, and the overwhelming weight of their responsibilities. The couple appears in almost every outing of the series, but their story can be beautifully told in a small collection of episodes.
"The Avatar State" (Season 2, Episode 1)
In the tense second-season premiere, Aang, Katara, and Sokka visit the Earth Kingdom General, Fong, ahead of their journey to Omashu to find Aang's desired earthbending master King Bumi.
The deceitful Fong, having heard of Aang's display of raw power during the siege of the Northern Water Tribe, designs a series of tests to attempt to trigger Aang's Avatar State - a plot that culminates in Fong submerging a hapless Katara in the ground. This life-or-death situation does indeed trigger the Avatar State, but more than that, reveals that Katara is the one thing Aang cares about above all. It's a brutal but effective moment of characterization for Aang, as Fong and viewers alike discover that his ultimate weakness is also his ultimate strength.
"The Serpent's Pass" (Season 2, Episode 12)
Viewers - and Katara - see a different and altogether troubled side of Aang in this danger-filled episode. Disturbed by the way he himself was consumed with anger after losing Appa in the desert, Aang takes on a serious persona and seems to distance himself from those around him, including a supportive Katara.
As Team Avatar leads a family of refugees across the dangerous Serpent's Pass, Aang and Katara must combine their bending powers to fend off the vicious serpent and ensure the party's safety. In the end, after one of their companions gives birth and Aang meets the newborn, he has a heart-to-heart with Katara in which he apologizes and reiterates how much Katara means to him. It's a sweet episode that shows Aang's emotional growth and the depth of his and Katara's bond.
"The Day of the Black Sun, Part 1: The Invasion" (Season 3, Episode 10)
Aang and Katara share a brief but impactful moment together in this episode that depicts the Gaang's thwarted invasion of the Fire Nation. As Aang prepares to fly off to confront Ozai, he and Katara share an intimate goodbye, with each party having a lot to get off their chest.
Katara expresses how proud she is of Aang's growth and maturity, while Aang faces the reality that once he leaves, he may not come back. While they're more best friends than a couple at this point, their feelings for each other are more and more evident, with the couple sharing their second-ever kiss.
"The Boy in the Iceberg" (Season 1, Episode 1)
In the pilot, Katara and Sokka discover an iceberg containing Aang and Appa. Aang and Katara's connection is immediate, as Sokka threatens the strange boy with his spear while Katara lays him down gently and wakes him from his slumber.
Once Aang is introduced to the Southern Water Tribe, he and Katara go penguin sledding and investigate a deserted Fire Nation ship, where he discovers with horror that he's been frozen for a hundred years. The silver lining of the whirlwind of a day, the pair agree, is that they met - and little do they know, their relationship will be among the most important the world has ever seen.
"The Guru" (Season 2, Episode 19)
In the penultimate episode of Season 2, Aang sets out to master the Avatar State after his horrible experience with General Fong earlier in the season. He visits Guru Pathik at the Eastern Air Temple, who assists Aang in opening his seven chakras.
Aang's main conflict in the episode occurs when Pathik reveals he must let go of his earthly attachments - including Katara - in order to open the final thought chakra. While deep in meditation, Aang realizes that Katara is in danger in Ba Sing Se and, against the Guru's advice, abandons his attempt at tapping into the Avatar State. Although Aang and Katara deal with separate hurdles in this episode, it's the first time viewers see Aang truly grapple with how much Katara means to him, even though this love might jeopardize his Avatar training.
"The Headband" (Season 3, Episode 2)
This episode is beloved for the fantasy of the normal life (in the Fire Nation, of all places) it allows Aang, Katara, and Sokka to experience as they lead an undercover existence in enemy territory. Aang inadvertently ends up at a Fire Nation school and endeavors to lighten up the town's strict and militaristic culture by hosting a dance party.
One of the most entertaining and revealing aspects of this entertaining episode is Katara's apparent jealousy over Aang dancing with a classmate, On Ji. In the end, Aang and Katara perform a cute routine together, but this intimate moment is interrupted when the party is raided. For fans of the couple, it's lovely to see what their relationship could be like outside of a brutal wartime context.
"Sozin's Comet, Part 4: Avatar Aang" (Season 3, Episode 21)
The series finale ends on a surprising but effective note, as Aang's dilemma over defeating the Fire Lord without taking his life is revealed to have been solved by the only remaining Lion Turtle. Once Ozai and his fleet have been disarmed, Team Avatar regroups at The Jasmine Dragon, Iroh's tea shop in a now-liberated Ba Sing Se.
Katara joins Aang on the balcony, and although they don't share any words, they don't have to. The pair's silent joy and relief is palpable, and The Last Airbender ends on one of its most beautiful shots ever: the sun sets over the city and, with no more obstacles in their way, Aang and Katara share a romantic kiss.
"The Fortuneteller" (Season 1, Episode 14)
In this sweet episode, a deeper dimension to Aang and Katara's friendship is suggested. While Aang has developed a crush on Katara, she is clearly not interested and, hilariously, reveals she thinks of Aang like she does Momo.
When the Gaang consults the psychic who calls the shots in an Earth Kingdom village, Aang eavesdrops on Katara's reading to see if she asks about him. He even consults an oblivious Sokka for relationship advice, but the episode's romantic subplot is quickly derailed by a Aang's discovery of an impending volcanic eruption. Besides establishing Aang's growing feelings for Katara, this outing's questions around destiny foreshadow the pair's joyous reunion in the series finale.
"The Ember Island Players" (Season 3, Episode 17)
In this deliciously self-reflexive episode, Team Avatar (now joined by Zuko) hides out at Fire Lord's Ember Island beach house and discovers that a play is being staged about their lives. Besides cleverly recapping the series thus far, the play provides the grounds for Aang's attempts to express his well-established feelings for Katara.
For her part, Katara feels conflicted about pursuing a relationship with the Avatar in the midst of a war when so much is at stake, and Aang does a less-than-perfect job of hearing her out. As the series's final showdown looms in the distance, the fate of Aang and Katara's burgeoning romance seems uncertain. It's not one of their happiest times, but it provides a necessary lesson in communication and boundaries.
"The Cave of Two Lovers" (Season 2, Episode 2)
This episode is easily the most romantic of the entire series, tying together a tale of long-dead star-crossed lovers with the burgeoning love between Aang and Katara. On the way back to Omashu, where Aang hopes to recruit King Bumi as his earthbending teacher, Team Avatar must pass through a maze of tunnels.
Aang and Katara are separated from the rest of their travelling party and discover via engravings on the tunnel wall the story of Oma and Shu, a couple from warring towns who learned earthbending from the badgermoles and created the underground network to meet up in secret. Though just friends at this point, the couple shares their first momentous kiss in tunnels under the waning torchlight.