During the first two seasons I didn't much more than a somewhat cliched story with cliched characters. But towards and into the third season things started to develop a lot. First was the turning of Zuko and then that was quickly followed by the training of Sokka and we've got two developed characters and most important more badass.
This episode on the other hand shows why season 3 is such a better season than all of the other ones before, as we constantly get new situations and original plots that make for an exciting ride. This episode reminded me a little of Prison Break and how in a situation like this one must sacrifice something in order to get other things done. I will try not to spoil it to much but the interactions between Sokka and Zuko are great, the story is very catchy and keeps you involved till the last moment, and apart from that there are some old characters that come back in the story making for a very interesting and unique episode of Avatar.
This last half of the season was amazing with fantastic episodes that made the previous two seasons look like children cartoons (although that's what they are, but you get the point...) and this episode is a strong evidence towards that.