Warning: Spoiler Warning
Sooooo ... Beckett is now an FBI agent ... and they're gearing the season up as though she's going to be there for a while, cuz it sounds like they're trying to make a new Big Bad for the series (now that they seem to be done with her mom's murder); and it looks like they're trying to have it be whatever this ghost base is. I can understand wanting to bring something fresh into the show, but I don't like that they're taking Beckett away from NYC or the boys (the boys were not in this episode nearly enough, not by far). And the fact that they're having her so far away, and with the FBI now ... Castle and the boys aren't going to be able to help her on cases (which Castle only proved when he started poking around after he got ahold of the picture that she dropped). So, there's got to be a point where the writers are going to bring her back to NYC and have it so that the boys can still work with her.
I don't see her coming back and becoming captain, and not just cuz Gates is still there ... she doesn't seem like she wants to be the captain (at least not yet). She still seems like she wants to be out there solving cases and not have to put up with the BS that comes with the job.
So, maybe realizing that Castle is so close to death, she'll realize that she wants to be closer to him once they find the antidote, and she'll go home? I'd love to say that I think that the writers of this show would be above doing something as pedestrian as that, but I can't. They've proven over and over that they are willing to go for the easy out on stuff. That isn't to say that I don't still enjoy the show (even though I want to pull Beckett's hair in every. single. episode.), cuz I do (and if I didn't, I wouldn't still be coming back). But sometimes there are things in the grander scheme of things that I wish didn't seem kind of predictable.
Also, I'm really hoping that this doesn't prove to be a repeat of season three (where the entire season felt ... off. Kind of like the odd/even thing with ST, but every third with this). That season almost seemed like there were some sort growing pains going on, and they weren't really able to get back in the grove again ... at least not wholly (since there were one or two episodes that still seemed like the show), and it didn't come back again until the next season.
So, here's hoping that things work out this season so that they're kind of awesome.