Not only will I say that this is the best episode of Avatar: The Last Airbender, I will say that this is one of the greatest episodes of any TV show that I have ever seen. It's definitely up there with the likes of Breaking Bad's Ozymandias.
First, right off the bat, Mae Whitman delivered an absolutely stunning performance as Katara in this episode. She captured every single emotion that Katara felt throughout the episode perfectly, from young Katara's fear, to present day Katara's anger and grief. This is a show that has a lot of stand out performances, but Mae Whitman throughout this entire episode takes the cake, no doubt.
Animation wise, this is also one of the best, but Avatar never really had a problem in this regard, all of its episodes are beautifully animated. To me though, this one stands out from some of the others.
The writing was fantastic. This episode was written by Elizabeth Welch Ehasz (the wife of series head writer Aaron Ehasz), who has written some of Avatar's best episodes, such as The Avatar and the Firelord, Zuko Alone, and Appa's Lost Days. But by God does this one stand far and above the rest. How Katara's character was handled this episode was what made it so incredible to watch. It's odd to see the usually caring and compassionate group mother become so hell bent on revenge and letting her anger and hatred consume her to the point where she goes down this dark path, but it never once feels out of character. All of it is quite in character for her, and we've seen bits and pieces of this behavior appear in previous episodes, but this is the one where it all just comes pouring out, and boy it is great, but also hard, to watch.
Similarly, the direction, handled by Joaquim Dos Santos, was masterful. He only started working as a director for the series come Season 3, but he quickly established himself as one of the series' best directors. Some of the shots in this episode are just so memorable. It was especially focused on Katara, using a lot of close ups on her, and in those shots, you can really see the pain in her eyes. Eyes that are usually so heartfelt and filled with hope are replaced with a desire for revenge.
And the culmination of all of this is in the episode's climactic scene, which is easily one of the best scenes in the series. In this scene, Katara proves herself to be so incredibly strong, not just through her bending prowess, but in her final decision. It's beyond amazing that a kids show can be this thought provoking and deep, especially with the episode's final message. This episode is truly a masterpiece.
