The episode will be called "The Rapture" and we'll meet Castiel's vessel, named Jimmy.
First, as I had previously commented to kitsu84 just before the episode description came about, my original theories about Castiel's vessel were flipped around based off of what the episode is truly going to be about. How I predicted it would go: it would've been a flashback episode, where Castiel was a priest or preacher or someone within the religious community; was a family man, faithful and loving and normal. Until something tragic happened, something of the supernatural nature like, for instance, Lilith taking possession of his daughter and he would have to try to take the demon out, but with limited knowledge he couldn't. So his entire family was in danger and he failed to save them in time. So in the end it would be revealed that, after their funeral/memorial he would go to his church and pray for guidance and some divine assistance in getting justice for his family's death. That is when Castiel answers his prayers, which would make the connection between him, the vessel, and the Winchesters much stronger from that alone. It would be benefiting them all in a way.
The official description kind of Kripke'd my theories, of course. But nevertheless the underlining basis of the same lines is there, about the vessel and his family and him or his family being in danger. Just in present time.
Which leads me to the obvious question: where is Castiel?
In the description it says that Castiel appears to Dean in a dream telling him he has something important to discuss and they need to meet privately, but then he disappears so they try to find him. But find the human host instead. This has me pondering whether this is simply a test or if Castiel is in trouble with his superiors, like whatever he was planning on telling Dean was going against his orders so they had to "pull him out" to prevent that from happening. Allowing the human vessel to remain intact. Because honestly I thought that once taking possession of the vessel he couldn't leave, in fact everything we've seen so far says that even when they appear and disappear the angels often will keep that body until their mission is completed. If Castiel left the vessel for whatever reason, it cannot be good.
Also, keeping in mind the deleted scene from "Lazarus Rising" Castiel mentioned that it was impossible to find a human vessel durable enough to contain him. So, unlike demons, angels cannot just randomly body-jump from vessel to vessel. Whatever made Jimmy the "right" vessel for Castiel is something I'd like to know, as well. What did Jimmy pray for? What was his plea to God?
Taking a look at the promo stills, without being distracted by the pretty for a moment, it appears that Jimmy returns home. Wherever that home is I'm not sure, some have commented that there's a lack of a wedding band on his finger, indicating he wasn't married. The two adults he's with may be siblings, cousins or other relatives, and the little girl he's embracing might as well be his daughter (which may very well be Lilith!possessed by that smile plastered on her face while he's looking all mournful and sad). So my predictions is that he was a single dad before handing her off to his other family to do some work elsewhere (church or business or whatever) and that's when he was taken possession by Castiel after praying for whatever. I'm not entirely sure. Because if the vessel has a family wouldn't they have been missing him all this time? Unless he was a man that worked around the clock and traveled a lot, but I have no clue.
But how will the Winchesters convince him about Castiel, about the danger he's in? Will he recognize Dean, or will Dean be able to get through to him? Does he realize that what he prayed for might be too much to handle, if he indeed pray for something like being part of a divine purpose? How will all this play out? OMG GIVE ME THE EPISODE NOW DAMMIT!
This came out longer than I'd anticipated, but that's what Misha/Castiel does to me I guess. Makes me all thinky with thoughts regarding his character, because I do love him so. ♥ I'm excited for this episode, as if you couldn't tell. KEEP IT COMING KRIPKE, KEEP UP WITH THE CASTIEL LOVE! AND THE DEAN/CASTIEL APPRECIATION!