

In a bid to earn Katara's trust, Zuko helps her track down the Fire Nation general who murdered her mother. "The Southern Raiders" (book 3, episode 14): Picking up where "The Puppetmaster" left off, this late season 3 entry further explores Katara's dark side and allows her to be understandably flawed. Plus, it's always fun to see Aang get to be a normal kid, showing off his ~flameo~ dance moves and teaching his classmates how to loosen up. " The Headband " (book 3, episode 2): With the Fire Nation set up as the bad guys, the episode did a great job at humanizing its people as everyday citizens caught in a war, just like people from other nations. No other Spirit World denizen is as compelling as Wan Shi Tong, the owl librarian so pacifist that he's willing to kill rather than let more people twist his knowledge for violence (which, like the best A:TLA episodes, really makes you think). It's also very important to Team Avatar's journey, kicking off Appa's tragic captivity and pointing the way to the Day of the Black Sun. "The Library" (book 2, episode 10): This adventure is a blast of fantasy, from the Borgesian desert library to the "sandbenders" who move and dress like the Fremen of Dune. Even more than that incredible power sphere of elements, Aang's insistence on doing so is what finally makes him the Avatar. "Sozin's Comet" retains its power years later, especially at a time when Americans are openly thinking about what justice means: Should officers of the law have a license to kill in the line of duty? Is it humane to incarcerate people for years? May each of us, when we arrive at our moments of triumph, retain our humanity enough to question the consequences of our actions. Thanks to the long-awaited appearance of the wise Lion Turtle (the ultimate animal hybrid, whose existence was hinted throughout the series), Aang learns that he doesn't have to kill his enemy when a more righteous solution is available: Taking away the power that Ozai used to justify his imperialist slaughter. But only at the end, when he has mastered all four elements, does Aang think about what it would actually mean to "defeat" the Firelord.

For three seasons, Aang has been training to become more powerful than Firelord Ozai.

One of the best series finales of all time (certainly in kids' media) wasn't afraid to flip your expectations. Sure, the series finale has a slight advantage in this ranking since it's the length of four separate episodes, but the primary reason "Sozin's Comet" gets the top spot on this list is because of how perfectly it resolves all the plotlines and character arcs that built up over three seasons.
