Chapter 53 (Bran VI): Robb is maturing a great deal. He's about to make his first major decisions as the acting Lord of Winterfell. The banners are called, and it doesn't seem like many of the bannermen are willing to take a fifteen-year-old boy seriously as their commander. Going by the numbers Luwin has told Bran, Robb has a sizable army built up. Rickon, being a young kid, is highly impressionable, and isn't taking everyone he loves and holds dear leaving all that well. He hasn't seen either of his parents or his sisters in nearly a year, and hasn't seen Jon is just as long. I'd caught a few hints of something going on with him before, but now it's come to the front. Now he is having to deal with Robb going as well. In his mind, none of them will ever return. These things leave deep emotional scars. I hope to see more of him as he gets older. Hodor.
Chapter 54 (Danaerys VI): Looks like the Dothraki just became more of a threat. Drogo starts off with no intention of going after the Iron Throne, after we've been repeatedly told throughout the book that the Dothraki hate ships. But then Robert's order of assassination against Dany comes through to the area, and someone tries to actually kill Dany. Not only does the try on her life fail, but it backfires badly. Before, there was no chance the Dothraki were a threat, even when Viserys was alive (especially when Viserys was alive, perhaps) just cause they wouldn't cross the water. Now Drogo is angered enough that he is willing to invade Westeros. Also, this is really the beginning of Dany showing much interest in the Iron Throne herself, rather than just being her brother's pawn in an attempt to get an army for his try at the throne. More stuff with the dragon eggs. GRRM couldn't have telegraphed things more obviously on that front.
Chapter 55 (Catelyn VIII): Catelyn is finally back with Robb. We finally learn some of what happened to Lord Beric's force that was sent to kill Gregor. Things didn't go so well for them, it would seem. I wasn't expecting them to do well. Ned has taught Robb a lot of command and tactics, but Cat shows him that he still has some things to learn, and there are some things that only actual experience can teach. Also, it is Cat, not Robb, who first sees the letter from Sansa as being what it really is: a hostage letter.
Chapter 56 (Tyrion VII): The first interesting thin about this chapter was that Masha was executed , no doubt for allowing Tyrion's abduction by Cat, and the way that Tyrion reacts upon seeing her body. "A room, a meal, and a flagon of wine, that was all I asked." And then the clansmen burst back into the scene. Shagga sure has a thing for chopping off manhood and then doing something nasty to dispose of it. Tyrion is still riding with the assorted clansmen, whether he wants to or not. It still isn't certain if he is in charge of them or not, the chapter ends with him more of a hostage.