Warning: Spoiler Alert
The return of Henry Winchester, and now we find out how exactly Abaddon first possessed Red. I guess that it's interesting that she decided that she would have let herself become possessed by a Knight of Hell cuz of love? I'm not sure that that would have been at all interesting as far as the progression of the mythos of Show if we didn't also take into account the fact that love first turned Cain into a demon (and into the first Knight of Hell, and the trainer of the other Knights). The only thing that really makes it interesting to me is the idea of what could possibly end the Knights. Sure, we have the First Blade, and that's really going to be what it is that kills both Abaddon and Cain, but I think that it would actually be much more interesting if it were love that had been the thing that had killed (or ended) the both of them (since that's what first turned Cain into a demon, and what allowed Josie to become possessed). It would certainly would have made a much more interesting dynamic to the story as a whole.
I kind of wanted Sam to tell the ex-nun that he was Henry's grandson, and I'm not entirely sure why he wouldn't have. I almost got the feeling that he thought that she wouldn't have believed him if he told her the truth, but I don't think that that's what they were really going for (since I don't see why she wouldn't have believed him after what she had seen ... and seeing as how she seemed to understand who he was after the fact).
I want to know what it is that Crowley has going on, since he certainly has something planned (something in which he is trying to manipulate Dean into doing). I really want to believe that it is something more than making sure that Dean kills Abaddon (and doesn't kill him), since that seems too obvious a thing to happen ... since that's what they've been working for already anyway. I want it to be something much more sneaky and underhanded (which may lead into the final season), but I have a feeling that since we're dealing with Show here, we're going to end up getting Kripke'd (even though he hasn't actually been working on Show for three and a half seasons). So, I'm not going to hold my breath that there's going to be anything more important or exciting going on.
Also, how is it that Dean was so tricked by a demon pretending to be a hunter. Wouldn't he have known when someone was pretending to be one of them, instead of actually being one of them? The guy seemed a little bit too obvious about what he was about to do ... and ignored Dean a little too much (for someone who was hanging out with the King of Hell) for him to have not become suspicious about what was going on. I suppose that we are meant to forgive him for that seeing as how he has been so focused on trying to figure out how to find Abaddon, and it has maybe given him brain-fever enough to make him miss things that he may have normally noticed.
So, Abaddon has been trying to create her own army by stealing people's souls. I suppose that's kind of an interesting development. It seems that the boys are going to need to do more than just try to find Abaddon by going over and over the same records that they've been going over for the past month. Seems like they should be getting other hunters in on the job, if for nothing else so that they could try to find the captured souls so that they could be freed ... but I don't see that happening anytime during this season.