There is one word that very accurately describes the feel that this episode evokes: Majestic. After all, it does deal with Avatar Roku and Firelord Sozin, arguably two of the most powerful people in the known world of 'Avatar'. While this chapter reveals a great deal of very interesting history and explains much about the beginnings of the war, it ultimately comes down to a battle of the giants, of Roku's and Sozin's tense relationship, and its effects in the current storyline.
In many ways, this episode is an enhancement of 'The Storm'. It once again delves into the past, and it once again connects Aang and Zuko. But this time, the whole deal is much more powerful, the pasts much more significant, and the connection much deeper. While it doesn't necessarily answer any pressing questions, it does reveal a lot, and gives the whole backdrop of "the war" a personality of its own. Along with that, Zuko's family tree, something of a factor, becomes more transparent.
We only get to see snapshots of Roku's and Sozin's developing enmity, but that comes through from the story. Instead, what this episode really dishes out is visuals. Roku's trainings have some nice bending moments, and the scene at the end of it, where he bends all four elements at once, is made of pure eye-candy.
But even better than that is the battle against the volcano. Two powerful forces in an all-out battle to the death, with Roku trying to fend off everything the volcano is throwing at him. It has some very nice animations, and the sound effects and music fit perfectly. And when the second volcano also erupts, you can really feel all hope disappearing. It's a masterfully constructed scene, and shows just how much power the Avatar really wields.
Along that note, Roku does display a rather potent level of bending throughout the episode, along with entering the Avatar State at will. With Aang being the only Avatar the audience follows through the series, and with him still being an Avatar-in-training, so to speak, it's easy to forget just how powerful a figure a fully realized Avatar can be.
The ending of the account brings into mind the inevitability, and irony, of fate. Aang runs away from the Air Nomads, and in that process, ensures his survival, even though the trade-off is a hundred years of unstopped war. I really like the part where Sozin's ship sails over Aang's iceberg. Their paths came close, but it was not to be.
I have to admit that after such a grand episode, the ending was pretty bland. Suddenly, the gang, the very heroes of the show, seem so small, so insignificant, in light of the forces that have shaped history. That, along with Aang's interpretation of what he has seen, just can't outshine what was shown to us up to that point. Even Zuko's part was more interesting, because it was a surprise, something unexpected, something that actually has impact on the events to come.
Overall, this episode is great. It manages to push the plot forward, something that was lacking in the many fillers of this season, by showing the past, and it is filled with a good amount of action. After a weird episode like 'The Beach', it's wonderful to have this one, with a clear focus and a good story.