Guest stars: Courtney Ford (Kelly Kline), Elizabeth Blackmore (Toni Bevell)

Jim Michaels tweeted a picture where we can see a page of the script.

Here’s what I can make out of Dean’s lines to Mary:

“You lied to me. You said you’d keep me safe but the deal you made with Azazel - you saved Dad’s life but there was a catch.”

[Tight on Mary, Dean is getting to her]

“On November 2, 1983, Yellow Eyes Waltzed right into Sam’s room, thanks to your deal. After that…”

Other Spoilers/info (newest to oldest):

Conceptual photos on the episode involved shots of drug dens and over doses - I have no idea how this will play out.
Shooting was done in a park
Scenes in the bunker with red alert lights on
There is a scene where Dean confronts Mary about her deal with Azazel.
Seattle Con to occur during filming

PRE-FINALE: As the British Men of Letters start to make their move, “people that Sam and Dean know/love pay the price,” forcing the brothers to take “a much stronger role in the wider hunter community” as generals, executive producer Andrew Dabb previews. Mary also faces a difficult battle with the Brits: She, “more than Sam and Dean, is on the inside, so her journey out may be a little bit more complicated,” Dabb notes. Meanwhile, Cas’ return brings “a lot of clarity” about “why he’s been in Heaven for so long” and “his own point of view on why he went.” And as the impending birth of Lucifer’s Nephilim offspring nears, “everyone is going to activate more and more.” Also on tap: the returns of Jody Mills and her surrogate daughter Alex, and “two surprise appearances, one by a relative newcomer and one by an old favorite.”

SEASON FINALE (MAY 18): The two-hour finale – the first episode deals with the Brits, while the second is Lucifer-centric – is “big and, I hope, somewhat bold and, in some ways, heartbreaking,” Dabb shares. The closer “also opens up some new stories for Season 13 in a very interesting way.”

“Who We Are” airs at 8PM and here’s how they describe that one:

FAMILY – Caught in a dangerous situation, Sam (Jared Padalecki) and Dean (Jensen Ackles) only have each other to rely on. Meanwhile, the fight between the American Hunters and the British Hunters comes to a head. John Showalter directed the episode written by Robert Berens (#1222). Original airdate 5/18/2017.

Castiel? Possibly. Crowley? No.

Guest stars: Samantha Smith (Mary), David Haydn Jones (Arthur Ketch), Kim Rhodes (Jody Mills), Elizabeth Blackmore (Toni Bevell), Katherine Ramdeen (Alex Jones), Anthony Bolongese (Youg Dean), Chelsea Gill (Paige), Courtney Ford (Kelly Kline),

Other Spoilers/info (newest to oldest):

There may be flashbacks to Dean as a young child.
This episode will focus more on wrapping up the BMoL and the finale will focus on the Nephilim
Sam, Dean, Jody, and possibly Mary all have scenes in Jody’s house.
Robert Berens visited set during filming
Some scenes were shot with Jody’s truck in front of her house.
Kim and Sam Smith were spotted filming together.
David Haydn Jones returned to LA after finishing his scenes for this episode. Elizabeth Blackmore as well finished filming so some Brits of letters will die or leave this episode,
No Rowena.
Sam and Dean have a scene with Jody on the phone.
Conceptual photos on the episode involved shots of drug dens and over doses - I have no idea how this will play out.
Shooting was done in a park
Scenes in the bunker with red alert lights on
There is a scene where Dean confronts Mary about her deal with Azazel.
Seattle Con occurred during filming

In the final two episodes of Supernatural‘s 12th season — airing back-to-back on Thursday — Sam and Dean face off against two major foes: the British Men of Letters and Lucifer. And even though the episodes are standalone stories, showrunner Andrew Dabb sees the two-hour slot as an opportunity. “We’re wrapping a lot of things up and certain plot lines will be ended this season — some forever and some temporarily — but also, that allows us to build up steam going into season 13,” Dabb says. “Coming out of the finale, people will have a pretty good idea of where things are going.”

When it comes to Supernatural, most finales can fall into one of two categories: Something that very directly affects the Winchesters (Dean becomes a demon; one of them ends up in hell) or something that affects, well, the entire world (the angels are falling; the Darkness is released). When season 12 ends, Dabb hopes they’ve created a finale that’s a bit of both. “There are some things that happen that impact strongly and directly on the boys, while at the same time, we are starting a new chapter in the show, [though] not in a way of erasing what’s come before,” Dabb says. “I think it’s something that will be a natural progression of what we’ve done but also cool and different and hopefully give us a lot of energy going into season 13.”

But what is happening in the finale isn’t the only draw. There’s also the matter of how it’s happening. Like some of the best episodes before it, this one will get a little meta. “Finales, by definition, can’t go too crazy,” Dabb says. “But I will say this: It’s by far the most meta finale we’ve ever done. There are some twists coming that we’ve never done before.”

Castiel might be an angel, but he’s made quite a few mistakes over the years. And the last time Supernatural fans saw him, he admitted just how much those mistakes have stuck with him. His past failures haunt him, and that will continue into the final two episodes of season 12. “I think that mindset has been driving Castiel for an incredibly long time,” Misha Collins says. “He’s somebody who’s just overwrought with regret about his past failures and he is continuously renewing his commitment to right his past wrongs, no matter what the cost. We get into that ‘no matter what the cost’ mode again in really stark relief in the finale.”

When it comes to protecting Lucifer’s baby — a decision Castiel recently made — Collins claims that Castiel truly believes he’s making the right choice, though the actor admits the angel is “really playing with fire” this time. Furthermore, Collins says, “There are going to be some fairly epic consequences in the season finale.”

And let’s not forget, Castiel still supposedly has to suffer some epic consequences from killing Billie earlier in the season, a decision Collins says will fold back into the finale. “As far as season finales go, this one’s going to be one of the more emotionally taxing and traumatic that we’ve had in a long time,” he says.

One bit of good news? Castiel’s decision to defend Kelly won’t put him at odds with the Winchesters now that Lucifer’s free. “The band actually does get back together at the end,” Collins says. “We’re all fighting against a common enemy at the end.”