This review WILL CONTAIN SPOILERS for the episode to be discussed, if you do not want certain plot points or story spoilt for you, please do not read further.
With the way that Supernatural left off at the Christmas break the show needed to step up and deliver something awesome to be able to compete with their cliffhanger, and boy does 'Devil In The Details deliver.
In an episode that explores the eleven seasons long mythology and manages to give us brand new and interesting stuff, the opening episode of the second half of the season delivers some laugh out loud moments, genuine tension, great character moments and a twist ending that will leave viewers picking their jaw up off the floor.
The episode opens with a bizarre and surreal scene as Crowley, acting like a child, opens his presents of Christmas morning as a depressed looking Rowena looks on. It's only when Lucifer, dressed as Santa gatecrashes that we realise this is a dream, or as Rowena laments a recurring nightmare, and we discover this is how Lucifer began to communicate with her from within the cage, organising the whole scheme to trap Sam with him. It's a throw away scene, despite showing us an important piece of the puzzle, but succeeds in the way that it delivers what has become a staple comedy scene of Supernatural, in which we get a little fourth wall breaking as Crowley gets a Sam Funkopop for Christmas.
Back in the real world Dean searches for confirmation that heaven were able to kill Amara with the equivalent of an Angel Nuke, where we discover that smiting from heaven causes a fallout that can kill humans, leaving Castiel as the only member of the team who can reach the blast point and discover Amara's fate.
In Hell Lucifer starts to take Sam on a tour down memory lane to try and make the point that Sam and Dean have gone soft, that the days where they'd be willing to do whatever it took to save the world had passed in an attempt to get Sam to agree to let Lucifer use him as a vessel in order to fight the Darkness. I can't help but feel that in some ways Lucifer has a point, that in the past Sam would have agreed to let Lucifer in in order to beat the even bigger bad, but the characters have moved on since those days and matured, knowing when not to make those kinds of choices. Unfortunately not everyone knows when not to make those stupid mistakes.
Castiel agrees to let Lucifer use him as a vessel in order to fight Amara, in a move that strikes me as massively stupid and immature. You'd think by now Castiel would have enough experience with the Winchesters to know that that kind of choice is definitely going to come back to bite them all in the arse. Can we fully blame the character though, is it because he apparently hasn't learnt anything? Or is it perhaps because the writers still don't know what to do with the character?
That being said, it's a hell of a development. It gives the season a whole new and interesting angle, it raises the tension and it makes things incredibly uncertain. Will Lucifer be true to his word to help fight the Darkness, and even if he does, what will the Winchesters do to get the Devil out of their friend.
Once the cat is out of the bag, for the audience and Crowley at least, Misha Collins is amazing in his new role. The second his facial expression and body language change it feels like Mark Pellegrino on screen. They way he acts and the way he talks if spot on and you can tell it's instantly the Devil in a Castiel suit.
The biggest shame with this twist is that the first thing Devileil does is to kill Rowena, in a move that has sadly become a standard for Supernatural, killing of interesting female side characters. Yes, I know that some of you might say that's not true, but think about it, Lilith, Ruby, Ellen, Jo, Meg, Charlie, Bela, Hannah, Anna, Naomi, the second Raphael and Abbadon, all killed off over the years in a pattern of Supernatural not giving interesting side characters a real chance to stay around. It's why I get scared every time Jodie Mills turns up because I'm worried they'll kill her off, and now they've gone and done it to Rowena too.
Other than that one gripe the show comes back to the air in a strong episode that plays true to the characters, introduces some new mythology as well as taking a look back at the history of our main characters. The twist with Lucifer is one of the more interesting things the show has done and sets the stage for some interesting new story lines to come.