So my fangirliness has gotten to me, and after watching the trailer multiple times, I caught a few things that could fill in the blanks for a lot of you other fans. This is purely prediction and "fill-in-the-blank" methods on my part, so don't razz on me for being wrong or anything. I'm just speculating what could happen based on what I put together through the clips.

First of all, thanks to DonBuFeng and Alisa for these screencaps, because without them I wouldn't have been able to figure this out without them having these resources available to me.

So this is what I concluded so far: The clips of Katara hugging Zuko, Katara waterbending those droplets out of the ground with Zuko behind her, the two of them jumping onto the ice in the water, and the closeup of Katara looking like she is bloodbending, are ALL from the episode "Southern Raiders." How would I know? Well, take a close look at these screencaps:

As you can clearly see (except for the closeup of Katara), they're wearing the ninja-looking outfits over their regular outfits. As for the second picture, Alisa didn't catch the screencap a split second later, which shows the sleeve of the ninja garb. I saw it while watching her version of the trailer, though, and you can even see of sliver of it on this screencap as well if you look very closely.

If I remember correctly, I read somewhere that one episode has Katara and Zuko going on a ninja-like mission. And judging from the masks on their faces in the screencap directly above, it's safe to say it makes sense, along with the fact that this could have everything to do with the title "Souther Raiders". I'm hoping this clears up a few things for you people who weren't sure if it was Zuko riding the ice with Katara or not.

As for the clip of Katara hugging Zuko...

Judging on the fact that they're still in their regular outfits, I'm thinking this may take place at the end of Southern Raiders, I'm guessing after they were successful in their ninja-like raid and whatnot. And if this episode has anything to do with Katara and Sokka's mother like the producers said it would, it would make perfect sense. Nothing against you Zutara fans, but judging by the look on Katara's face, it looks more like a "I forgive you" or "thank you" hug than anything else. Remember that Katara showed her weak spot for Zuko in "Crossroads of Destiny" because they both related to each other through their mothers. It could easily be concluded that Katara finally forgiving Zuko could have to do with the same thing, right? Especially if the raid had everything to do with Katara's mother, and the fact that Zuko probably helped her with the it because he can sympathize with her on the whole "losing your mother" thing.

Anyways, I think that's about it. Once again, I hope this helped some of you.

Uhh...Zutara fans, please don't flame me too much. I'm just trying to make sense of everything here, and although I'm a Kataanger, I really do have nothing against Zutara. Katara and Zuko just seem more than anything like companions and friends...but I won't start on that here, this thread is simply for possible clarifying purposes. Please save any major arguments for the Kataang/Zutara threads.

From what I've heard, "The Southern Raiders," will explain the death of Katara's mother using flashbacks. (ie: the Raid of the Southern Tribe) And those clips of Katart bending in a ninja outfit may take place during the finale, or a post-flashbacl part of "The Sputhern Raiders itself. The woman near the tree is Hamma, so Katara may go to her for training. (she may put morals aside upon relizing she may have to be relentless at this point.)

Going along with my Warden theory, from my guess, she may seek advice from Hamma, as she directly fought a Fire Navy Invasion team. (the part of my Theory which suggests the Warden and his team may act as villains for part of the Finale.)

If not, it could just generally be for training.