Indoors, Bobby slides a shot of holy water across the table at his newest guest. Ellen smirks a bit at this welcoming ritual of his, then easily downs the stuff with one sardonic eyebrow raised before sliding the glass back at her host with, "Whiskey now, if you don't mind." I know I've said this before, but I think I want to be Ellen Harvelle when I grow up. "You and me both!" And long story short? Pretzels saved Ellen's life. Yep, the bar's stock was running low, so she hopped out for a fresh supply, and while she was gone, Soon-To-Be-Ashy Ash called her up with "panic in his voice" and ordered her to look in the bar's basement safe should anything happen to him, right before the call cut out. By the time she'd sped back to the roadhouse, it was all over. Ellen then, like some sort of Amazonian rodeo gal, swings around in the air above her head a massive anvil about getting to live while so many of her betters burned to death, and once she's unceremoniously slammed the damn thing straight into Dean's forehead right between his eyes, we learn what she found in the bar's basement safe: A map of southern Wyoming with five Xs surrounding the Great Divide Basin.
The scene jumps ahead to the point where Bobby's discovered something of related importance in his extensive library. The five points on Ashy Ash's map correspond to five abandoned frontier churches constructed in the mid-nineteenth century by none other than Samuel Colt, he of the infamous Fucking Colt that everyone around here likes so much. Furthermore, the endlessly busy Mr. Colt built a series of private railway lines linking each church to the other. Guess what? The railway lines form a pentagram on the map. Guess what else? That pentagram is actually an enormous, "one-hundred-square-mile" devil's trap, constructed by the hateful Mr. Colt to imprison something in the "old cowboy cemetery" at the center of it all while keeping the entire area otherwise demon-free, for dark demonic forces sent from the flaming maw of Hell cannot cross iron lines, you see. Thus, the railways, and thus, of course, the recent swirl of demonic activity around those railways -- hundreds of the beasties are trying to access whatever the hateful Mr. Colt locked away over a hundred and fifty years ago. Sam, because he is super-smart even in zombie form, quickly realizes what Our Yellow-Eyed Acquaintance is up to with G.I. Jake.