Thursday night's Supernatural episode, "Two Minutes To Midnight," was one of the best episodes this season. Pestilence was nauseating, and Death was sublime. Prepare to have your mind blown . . . spoilers ahead.

This episode concluded the season-long arc about the Four Horsemen of the Apocalypse, four mega-demons whose power rings fit together to form a key to Hell. If the Winchesters ever hope to lock Satan back in his prison, they have to collect all the rings. And last week, that meant tracking down Pestilence, who is in the process of shipping Croatoan virus out to the masses via swine flu vaccine; and facing down Death, who is about to kill millions of people with a giant storm in Chicago. So it's a zombies-meet-2012 deathfest unless the brothers can prevail.

Making matters more complicated is the fact that Dean is no longer getting special treatment because archangel Michael has chosen another vessel, lost Winchester brother Adam. Plus, angel Cas lost his powers in that heavenly knife fight a couple episodes ago. And Bobby has decided to hock his soul to demon Crowley in return for Death's GPS coordinates. (Best part? Crowley seals his deals with a kiss, which he snaps on his iPhone just so he can show the Winchesters that he really did get some some tongue from Bobby.)

Pestilence and zombies

Written by soon-to-be-showrunner Sera Gamble, the episode began with a seriously disgusting look at a day in the life of Pestilence. He's holed up in a nursing home, masquerading as a doctor. Matt Frewer does a great job as Pestilence gleefully informing his patients that he's just given them a nice cocktail of flu, encephalitis, chicken pox, and various other things which cause rapid death - right after a bright green vomit missile exits their mouths. With some hints from Crowley, who almost seems like a good guy at this point, the brothers manage to track down Pestilence - only to nearly die in flailing piles of barf right at his feet. Right after he delivers a great speech about how disease is "very strong," unlike people who are sick.

Railing against God, Pestilence says, "Why does he pour all his love into something so messy and weak? It's ridiculous. All I can do is show him he's wrong one epidemic at a time."

And then Cas busts into the room - he took a bus to get there - and chops off Pestilence's ring finger. Instantly, the diseased brothers are healed. With a cackle, Pestilence notes, "It's too late." They've got the ring, but Pestilence's demon slaves over at the pharmaceutical company are shipping out trucks full of Croatoan-spiked swine flu vaccine. Cue a major zombie fight at the pharmaceutical company, notable mostly because Sam is so freakin awesome in the fight. He rescues everybody!

Oh, and also? Crowley really manages to do a semi-nice thing. He has written "a teeny subclause" into his contract with Bobby that allows the old hunter to walk again. "Totally worth your soul," Crowley snarks as Bobby looks at him gratefully. Crowley claims he's only holding Bobby's soul to prevent the brothers from killing him after dispatching Lucifer, but you really can't trust demons. Even ones who help your buddies walk again. (Plus, wasn't Bobby kind of badass in that chair? I liked his wheeled attitude.)

A perhaps-unwarranted concern

Plus, I don't know about you, but I'm worried that this Croatoan thing is going to continue to be a problem long after the apocalypse threat is gone. The first Croatoan episode was simply amazing - a series highlight - but I don't want it to become next season's arc. And with one more episode left in this season, well, you never know when you're getting some setup for next year. Anyway! It appears the Croatoan is contained.

Can Sam beat the devil?

Most importantly, the zombie scuffle reminds everybody how awesome Sam is, and how he has a core of goodness even though he's got that demon blood zooming through his arteries. Maybe his plan to let Lucifer into his meatsack, then hurl it into Hell, can work after all. Maybe he is stronger than Lucifer. Or at least strong enough to take Lucifer by surprise.

In fact, everybody but Dean seems to think Sam's meatsack plan is a great idea. Cas comes around to it, Bobby is cautiously optimistic about it - and even Death himself recommends to Dean that they go through with it. Which brings me to the most awesome part of the episode.

Death is in the pizzeria

After hunting around Chicago with Crowley, Dean finally finds Death in a pizzeria surrounded by dead diners. He's eating a deep dish pizza that actually looks dead. Instead of menacing Dean or giving long-winded speeches about the rise of Satan, Death is simply irritated. (See clip above.) He's an ancient creature, possibly older than God, and he considers Earth and its entire galaxy to be rather small potatoes. Somehow Lucifer has trapped Death with a curse, and Death wants out. So after comparing Dean with a bacteria, he says (not entirely unexpectedly) that he'll give Dean the ring.

But on one condition. Dean has to go along with the Sam-into-the-fire plan. No last-minute rescues. Death wants Lucifer locked up permanently so he can get on with his business elsewhere in the universe. so Dean lies to Death's face and says no problem about the Sam cast into Hell thing. And now he's got all four rings, plus Death's instruction manual on how to use them.

What was truly amazing about this episode

One of Supernatural's greatest strengths as a show is the way its writers play around with your expectations. No episode is ever about just one thing, nor is there even the typical plot/subplot structure. Like many of the show's greatest episodes, "Two Minutes To Midnight" felt like it told two interconnected stories that were equally important: One about Pestilence and one about Death. Most shows would have neatly bisected the two stories into two episodes that tidily wrapped up our Horsemen, but Supernatural went balls-out and finished the two Horsemen off at once. And you know why they could do that? Because the point in this show isn't some kind of "defeat the Boss" payoff. The monsters are beside the point, because the show is really all about what it means to be human.

At every turn in this episode, events went in a unexpected direction. Pestilence's worst threat wasn't his disease-inducing touch, but his ability to manipulate a pharma corp. Death's biggest concern wasn't how to kill 3 million people in a mega-disaster, but being trapped in our lameass galaxy. When Cas lost his powers, he got more badass rather than less. And Sam - demon-blooded, ambivalent, hulked-out Sam - is emerging once again as a source of goodness and strength.

Undoubtedly the best part of the show, however, was the way Death finally gave us the wide-screen view of the apocalypse that we should have gotten two weeks ago when we met the other gods. With his evocation of galaxies beyond our own, and his assertion that he will one day "reap God," Death makes it clear in just a few well-written lines that there are powers far beyond the ones orchestrating our wee Apocalypse. Suddenly we see beyond the confines of Judeo-Christian-Islamic whatever and realize that Death is a force that goes way beyond our conflict - or "above my paygrade," as Dean puts it.

This is the kind of smart, funny, mind-blowing stuff that brings me back to Supernatural week after week. You've got knife fights, and family drama, and then suddenly you're contemplating the way Death is the thread that passes through everything in the universe.