A great ending to a fantastic show. The third installment, aka Book 3: Fire, does exactly what you'd expect it to, wrapping up the show nicely whilst still jugging along at a fairly decent pace. I've really enjoyed watching Avatar and instantly feel, now that it's over, that my life is missing something, which is a small tell that you've just watched something excellent for me. I want to know more about Aang, his friends, and his world, but unfortunately that isn't really possible (well, except for The Legend of Korra, which is now firmly planted on my watch list for the future!).
After the fairly shocking ending to season two I was happy with the "flash forward" technique setting up the main arcs in episode one, except that I never really got on well with Aang's need to suddenly go it alone. I understand from a narrative perspective that they needed the kids to split off from the adults again, but the reasoning never pays off. Aang states he wants to battle the Fire Lord ahead of the invasion to reclaim his honour, but as their travels through the Fire Nation go on that initial logic is seemingly abandoned without explanation, instead just seeing the four main heroes travelling the long way to meet up with the invasion fleet. The silly thing about it all is that when they do, a much more logical explanation as to why the two groups needed to split up is forthcoming: on the one hand, travelling overland through the Fire Nation put Aang well out of the way (a hidden in plain sight manoeuvre) whilst allowing all of them to learn more about their enemies; on the other, the invasion force has travelled all over rounding up allies. Both of these are better reasons for them to split up then Aang suddenly going all emo-hero-mission on us, but oh well.
There are also a few small snippets which I feel could have been better integrated into the plot, such as Toph's meteor bending and the fact that Sokka gets given a white lotus by Master Piandao. These both get callbacks later on in the series, but neither feel particularly relevant; indeed, the white lotus is the barest of callbacks and not necessary at all, considering that Iroh unites the White Lotus anyway.
Minor quibbles aside, though, the character arcs and storyline developments in the third season are excellent. At long last we get to see Zuko flip sides (though not before we get to really explore his character, making his betrayal at the end of the previous season more than worthwhile) and join Aang, officially meaning that Aang has successfully united the four elements. Sure, it's a plot development that has been obvious from the moment we first met Zuko, but it doesn't make it any less satisfying. Plus, the way they go about it feels rewarding and justified, which is nice. Ditto Mai and Ty Lee's uprising and redemption; telegraphed, sure, but well done and meaningful when it came to a head.
It's also nice getting to explore the Fire Nation and getting to know the Fire Lord's story more deeply, including how the war began and the failures of the previous Avatar. All of this is brought to a head neatly when Aang goes in search for a peaceful means to end the conflict, one without death, and is failed by the previous incarnations of himself. Not one counsels anything other than a death sentence, which helps draw out the hopelessness of the epic four-episode long mini-movie. Speaking of which, I also really liked that the "Black Sun" story arc ended up being a dud, not just because it meant we got to see Aang and the Fire Lord embrace their full power with the coming of Sozin's Comet, but because it setup a different feeling second half to the season. We were still exploring their world, but the stakes had somewhat changed, and instead of travelling around it was a nice chance of pace getting to go on jail breaks, revenge quests, and dragon training, which all felt somehow more grown up then what we'd seen before, and that felt right.
It's also fascinating to see the slighter darker routes that the show treads in terms of bending. Both Katara and Toff learn about some of the "advanced" forms of control and manipulation that their powers allow them, which are fun extensions of the logic at the heart of the shows magic system. Toff's, of course, is a little more light hearted (and incredibly useful), but Katara's blood bending falling in the edge of mind control was an unexpectedly sombre consideration both of absolute power and of the mental toll that war takes. It also lends a huge amount more weight to her revenge plot line, which gives her a nice hint of real depth as a character you don't often see in a kids show. These are well balanced by Zuko and Aang's discovery of the wealth of fire bending capabilities, letting them both see that fire is not merely destruction but also light and life. That said, I was disappointed that Zuko's own journey didn't result in a dazzling light display in his fight with Azula; I feel it would have been fitting to see him master all the colours of fire and put her in her place, having boasted for three seasons of her control of blue fire.
I do feel like the way in which Aang ultimately wins is both clever and a little bit too deus ex. Sure, a giant lion turtle (I will miss this world's inventive animal mashups) tells him of a time before the Avatar when nature kept tabs on powerful benders, but it really wasn't a clear explanation and left you just a little confused as to what was going to happen. Even with the flashback I'm still not sure I know what was said between the two of them! Still, it gave us a truly epic final fight sequence, Aang unlocking his Avatar state and truly mastering the elements, will Toph, Suki and Sokka battle the air fleet, which felt pleasingly simple and still high stakes. On the other side of the world, I genuinely wondered at points if Zuko or Katara might not make it through, but again the fight was well paced and the conclusion, with Azula in chains having a meltdown, felt deserved.
Also, I really like that we learned that three of the four elemental bending techniques were first discovered by animals: dragons, mole badgers and air bison. They never mentioned where water bending came from though... Which wasn't the only mystery left over. We never find out what happens with Zuko's mother, or the ultimate fate of Suki and Sokka. As mentioned above, the white lotus and a few other small pieces are left in the air, but the most sinister was the demon Koh. When Aang and Koh meet, the demon practically promises to find Aang again, so I was expecting him to crop up – so much so that I thought the mysterious island was a trap of Koh's devising and Aang's insistence on seeing its face would be a major road bump! Still, no sign or mention of him, so I guess it was forgotten about or not as ominous as I thought. Also... the episode about the play was a bit weird and definitely a waste of time...
Finally, whilst I'm largely in the "children falling in love is creepy" camp, I did also cheer a bit when Katara and Aang kissed at the end. As I say, I'm sad to see the show end and lose these friends, but it was a great ride and I'm extremely glad to have taken it. It's still definitely a kids show, but the story and world building holds up well enough for anyone to enjoy.