The name of this dandy episode of
is "The Vessel", which can be taken many ways, for it concerns Castiel's problematic choice to let Lucifer occupy the Cas/Jimmy meatsuit in his (probably misguided) attempt to use Lucifer's power to finally vanquish Amara (aka 'The Darkness'). It can also refer to the WW II vessel Dean has to time-travel back to for this weeks mcguffin, a piece of the Ark - yes, a chunk of the Indiana Jones Ark- and we all know how THAT turned out! Time travel eps are usually pretty fun on Supernatural, but this one is deadly serious given the stakes involved.
Turns out the piece of the Ark is one of the few super-weapons 'touched by God' , which in theory have the power to vanquish this season's Big Bad. Originally found by Nazis in 1943, the Ark fragment was stolen by a Woman of Letters named Delphine, but not before she dispatched a Nazi soldier with the very effective Hairpin-in-the-neck attack. She attempts to spirit away the artifact on a sub back to the good ole U S of A, but the sub is sunk by the evil Nazi stain before she can bring the artifact back to the MOL bunker.
So the mission is set - Cas-ifer and Dean will McFly back to the sub, take the Ark and zip back before the sub is sunk -easy peasy, right? Kiddies, this is Supernatural, you know it's not that easy! Turns out Delphine added a sigil or two to keep nasty demons off the boat, so Dean lands in the sub while Cas-ifer ends up all wet-literally- in the ocean. So he whips back to Sam and gives him the bad news. But his Cas impersonation slips a bit and Sam begins to suspect that something is rotten in Cas-ville.
That's when Cas-ifer tries to pull Sam's soul out in an attempt to gain enough juice to travel back to the sub and take the artifact for his own gain. But Castiel bubbles up and takes control enough to save Sam.
Meanwhile, back in 1943, all hell is breaking loose. The bombing of the sub has commenced, and baddies are closing in from all sides. Delphine heroically takes the artifact in hand to obliterate the Nazi horde before Dean bites it. In true Indiana Jones style, she gets all glowy and explosive and incinerates the bad guys. Dean picks up the artifact with a cloth to protect himself and in pops Cas-ifer to beam Dean out before they end up in Davy Jones locker for the duration.
Now in the bunker, Lucifer grabs the Ark fragment to gain its power, only to find that Delphine's sacrifice has drained it of its properties, basically rendering it a doorstop. Of course this doesn't go over well with Lu, but before he can go all fire and brimstone on the boys Sam uses a blood symbol to make Lu go buh bye!
So all in all a good ep that advances the plot and sets up the final stretch-now the search is on for another 'Hand of God' weapon to use on Amara while trying to deal with Lucifer taking up residence in brother Cas.
One More Thing:
Lucifer playing Angry Birds in hell - very strong
And Another Thing:
Crowley as Lucifer's 'puppy' - priceless!