Our Intrepid Heroes track Pestilence to a nursing home in Davenport, Iowa, where The Horseman's been posing as the home's resident geriatrician as of late in order to conduct a series of gruesome experiments on some of the patients, each of whom ends up dying of multiple infections from an exotic variety of rare tropical diseases. When his demonically enhanced assistant informs him of Sam and Dean's arrival, Pestilence unleashes a plague that instantly slaughters the remaining patients and staff, then afflicts the boys with a combination of meningitis, scarlet fever, and syphilis that brings them to their knees. Fortunately, Castiel shows up at the very last minute to save the day. Unfortunately, his wacky Angel-B-Gon antics in Van Nuys have left him far more human than angel at this point, and he, too, nearly succumbs to Pestilence's pestilence, but he somehow manages to hold it together long enough to hack off The Horseman's ring finger with The Knife That Can Kill Anything Except When It Usually Can't. Before Pestilence vanishes, though, he warns Sam and Dean that "it's too late." DUN!
Meanwhile, we learn that Bobby took Crowley up on the latter's end-of-episode offer last week, and Crowley's little spell revealed the following bit of very bad news: Chicago's about to be destroyed by a thunderstorm that somehow sets off a cascading series of catastrophic natural disasters which in the end will leave more than three million people dead. Good thing I moved. The final Horseman's behind it, of course, and Our Intrepid Heroes are about to roadtrip on over to Illinois when Crowley drops another little bad-news bombshell on their tantalizing derrieres: Niveus Pharmaceuticals issued a press release announcing countrywide distribution of their new, faster-acting swine flu vaccine which is actually, of course, the Croatoan virus, so by this time next Thursday, the boys plus their remaining allies should be living in Zombieland. D'OH!
The gang decides to split up, with Sam, Castiel, and Bobby heading back to Nevada to put a halt to the Croatoan distribution before it begins, while Dean and Crowley trot over to Chicago to kill Death. After a thrilling firefight in Niveus's warehouse, the Nevada posse succeeds in destroying the zombie virus. Dean, however, fails to off Death, but he's in luck, for Death's sick and tired of being tethered to tantrum-throwing spoiled brat Lucifer, whom he'd like to see reimprisoned perhaps even more than the brothers. To that end, Death voluntarily presents Dean with his ring, and even goes so far as to offer Our Intrepid Hero a comprehensive lesson on how to use the things.
And while all that's been going on, our fearless protagonists and their feisty sidekicks continue to debate the relative merits of Sam's astoundingly stupid plan to say yes to Lucifer, then wrest control of his body back from the archangel long enough to hurl himself into Lucifer's divinely constructed cage. Can you believe these morons are actually going to go through with it? Idiots.
Rattle, Rattle THEN! Adam Milligan got trapped in Heaven's Green Room with the rapidly descending Archangel Michael, Castiel obliterated himself with an Angel-B-Gon sigil he most awesomely carved into his own chest, the recently deceased Archangel Gabriel sent Our Intrepid Heroes a posthumous message regarding Lucifer's divinely wrought cage and the role The Horsemen's rings play in locking it, Crowley offered to lead Our Intrepid Heroes to Pestilence, Niveus Pharmaceuticals planned to unleash the Croatoan virus upon the planet by tampering with a vaccine for Mexican Influenza, Capital-D Death rose at Lucifer's bidding in Carthage shortly before Thanksgiving, Crowley proposed "borrowing" Bobby's soul in order to triangulate Capital-D Death's current coordinates, Darling Sammy drunk-dialed Bobby to discuss an Apocalypse-ending plan of stupendously asinine proportions, and wow. That THEN! was pretty damn plot-tastic, wouldn't you say? Let's see if the episode itself manages to do the same.
Rattle, Rattle NOW! The NOW! creeps towards the front of the screen, only to vanish in a cross-fade that lands on the nighttime façade of the Serenity Valley Convalescent Home in Davenport, Iowa -- Quad Cities represent! -- after which we head inside to one of the patient's rooms. "Doctor Green!" the fragile-looking woman on the bed smiles as her as-yet-unseen physician enters from the hall. "How was your trip?" "Very productive," the good doctor answers with a grin in his voice, and once he crosses the room to perch on the edge of her bed and take her hands in his, the camera reverses to reveal...Pestilence! Looking rather homey and avuncular and not like a plague-carrying Horseman Of The Apocalypse at all! DUN! "And how are we tonight, Celeste?" Doctor Pestilence asks with large amounts of false sincerity and concern coloring his tone. "The nurse says you can't sleep?" "Oh, I just feel worse and worse," Mortally Imperiled Celeste wearily complains. "Well," Doctor Pestilence cheerfully explains as he dons his reading glasses, "that's because you're suffering from a combination of the common cold, Dengue fever, and a nasty, nasty case of Japanese encephalitis!" "I'm...sorry?" Rapidly Deteriorating Celeste murmurs, thinking she misheard him, but Doctor Pestilence confirms his diagnosis with a grin, then passes a hand across her face. Instantly, a constellation of ragged red blisters erupts across her wan skin as Doctor Pestilence realizes, "You never had chicken pox as a child!" "This," he promises, giddy as a schoolgirl, "is going to be fascinating!" "But, how could I...?" Quickly Fading Celeste murmurs, barely able to get the words out at this point. "Have all those diseases at once?" Doctor Pestilence finishes for her. "Well, it's a proprietary blend," he happily explains. "I mix it up in a Petri dish, the Petri dish being...you!" "Are you gonna cure me?" Soon-To-Be-Dead Celeste whispers, drawing a frail hand to her hyperventilating chest. "No," Doctor Pestilence replies. "You're going to die -- in 4, 3, 2..." "HUAAAACK!" A fluorescent green spray of split pea soup thwacks Doctor Pestilence on the side of his face as Almost Totally Dead Celeste horks up several severely diseased internal organs before allowing her head to drop limply to one side on her pillow, by now most thoroughly deceased. "Interesting," Doctor Pestilence observes, yet another sly grin tugging at the corner of his mouth right before the audience gets thwacked on the side of the face with the...