It's hard to believe that "Slumber Party" is only the fourth episode of "Supernatural" of the season.  I'm already emotional wrung out from Castiel's exile, Sam’s near-death, and Dean’s secret, so it's refreshing that this week's installment welcomes back honorary Winchester Charlie Bradbury (Felicia Day) and went back to its roots of exploring classic monster tales.  And what's more scary than a portal to another dimension that's home to a wicked witch, flying monkey and a man made of tin?  

Grab your ruby slippers and let's dive in, shall we?  

The episode was peppered with black and white flashbacks that were beautifully shot, impeccably scored and well acted.  In the two Men of Letters members—a veteran named Hagarty and a rookie named Jenkins—a holed up in the bunker for an assignment.  The starry-eyed Jenkins believes that the lair is the "last true beacon light in a world that's gone topsy-turvy…the epicenter of the ultimate chess match between good and evil."  But even that rosy perspective wilts from months of boredom.  Dorothy arrives with a tongue-less Wicked Witch from Oz.  She had captured her and returned in our world to figure out how to kill her after beheading, bullets and fire didn't work.  She cut out her tongue to keep her from casting spells.  

Our haggard old Wicked lives up to her name and reputation by escaping her bonds and possessing poor thriller-seeker Jenkins.  Hagarty kills Jenkins and Dorothy, who is infinitely more badass than the Judy Garland variety, binds her soul with Wicked for eternity.  Or, at least, 78 years when Sam and Dean knock over the jar containing their souls when they attempt to fix the magical supercomputer that powered the Batcave's lockdown when the the angels fell.  

Our precious, bighearted Sammy still doesn't understand why Castiel left (Dean's explanation of "he felt like he'd bring trouble down on us" didn't hold water) and is searching for a way to help him.  He figured out that the table map lit up, and marked the locations of clusters of angels when they fell in last season’s finale.  Sam wants to "hotwire" the computer so it can track angels.  Even Dean is impressed by the idea, however I wonder if he should be alarmed that the computer’s first discovery might be the angel camped out in Sam's healing fine bod.

They enlist the services of their favorite hacker, Charlie.  She quickly raves about the computer, which has some kind of encryption, tracks "global badness" and has no discernable power source.  Maybe it runs on the power of souls or the tears of “Supernatural” fans?  

After a lot of "Game of Thrones" and even more beer, Charlie discloses that she's been hunting monsters that would make for a great YA book series, a ghost and a teenaged vampire, and while it was "intense," she didn’t find it magical.  “Where are my whitewalkers and volcanoes and a magic ring to throw in the damn thing?  Where's my quest?" 

Sam is no stranger to supernatural trials and admits that they are "all deadends” and that they “suck.”  I would love for Sam to share more about how he’s mentally recovering from the trials, because he's barely said a word, but if that happens I might need Zeke to revive me.