Anna the angel's escaped from Heaven with a grand plan to avert The Apocalypse, and invades Dashing El Deano's stripper-filled sleepytime to plead with him to meet her somewhere industrial and deserted so they might chat about everything in person. Castiel, no fool he, forbids Our Intrepid Hero from leaving this week's motel room and heads off for the assignation in Dean's place, and after a bit of sniping, Anna lays it all on the line: She intends to slaughter Darling Sammy, then scatter his atoms across the universe to prevent his resurrection. With Sam thus out of the way, her thinking goes, Lucifer will have no choice but to abandon his current course of action, especially after he finally burns through his temporary Vessel. Castiel is, of course, shocked and appalled, and warns Anna that should any harm befall either of the Winchesters, Castiel himself will see to it that Anna's terminated with extreme prejudice, so what does Anna do?

Zap herself back in time to 1978, naturally, where she intends to off the younger versions of Burnt Mary and Sucky John before they have a chance to reproduce, thereby bringing a halt to The Apocalypse by ensuring Sam and Dean never existed in the first place. Castiel immediately smacks the boys plus himself back to 1978 as well, but the effort leaves his much-weakened angelic form unconscious and drooling blood onto the sidewalk, so Sam and Dean sling him into a motel room for the duration and set off to save their parents themselves. It goes about as well as we've come to expect from such shenanigans on this show, and after Anna -- with a crucial assist from a years-younger Uriel -- hurls Less Sucky John through a wall, sporks Darling Sammy with an iron pipe, and makes to rip Unburnt Mary's head from her shoulders, St. Michael The Archangel finally decides to grace us all with his presence by asking for and receiving permission from a grievously injured Less Sucky John to inhabit the latter's body, after which he chars Anna to an ember, banishes Uriel elsewhere, and yaks Dean and the audience to death about determinism before pushing The Great Big Red Reset Button In The Sky to heal everyone, knock Dean and Sam back into the present, and wipe all memory of this week's adventure from Less Sucky John and Unburnt Mary's minds. And in the end, Our Dear Boys draw the episode to its close by toasting to Free Will, because Dimwit El Deano apparently didn't listen to a single goddamned word Michael said.

Meanwhile, Capital-D Death has long since lumbered on from the blackened remains of what used to be Arkansas and has now set its sights on the 7,600,528 people in Mississippi and Alabama. Whoops!