Recent episodes have suggested that the momentum generated at the start of the season might have been faltering in the build-up to the "winter hiatus". However, after a few weeks off (in the States), the show has come back with its batteries recharged and looking to knock it out of the park with The Devil In The Details.
While there is a degree of violence in this episode (it wouldn't be Supernatural without it, right?), this is a largely cerebral story, dealing with the psychology of the characters as the various forces in play try to manipulate one another to their own ends.
Sam is trapped in The Cage with Lucifer, who takes him on a stroll down memory lane, literally walking him through his memories, and trying to convince the younger Winchester that he has lost his edge, and isn't strong enough to face The Darkness.
Quite rightly, Sam still refuses to let Lucifer 'use' him to escape, pointing that even if Lucifer is strong enough to beat Amara, that would still result in The Devil being loose in the world, leading to an inevitable apocalypse.
Castiel investigates the site of Amara's smiting, and discovers that she is not as dead as people might have hoped, and gets turned into her messenger... sending him to rendezvous with the others in Hell to proclaim that she "is coming".
With some guidance from Crowley, Dean obtains an artefact from Bille (Lisa Berry), the reaper with a special interest in the Winchesters, and heads to Hell to help Crowley control his mother, and use her to free Sam from his imprisonment with Lucifer.
As might be expected, things don't run according to plan, Rowena ends up hoisted by her own petard and Lucifer's masterplan (or is he just grabbing an opportunity when he sees it?) is revealed.