Dick Roman acquires Frank's hard drive that contains sensitive information about the Winchesters and gives it to an unsuspecting brilliant hacker named Charlie telling her she has 3 days to crack the encryptionl or she is fired. Sam and Dean are tipped off that Dick has the hard drive and race to get to Charlie before she breaks the code. Meanwhile, Bobby tries to help the brothers, but his rage towards Dick for killing him starts to get in the way.

Sam and Dean investigate the mysterious deaths of two LARPers (Live Action Role Playing) who were playing a game entitled Moondoor. The guys are thrilled to discover the Queen of Moondoor is none other than Charlie. The three learn that a fairy has been commandeered to harm people and the only way to stop her is to find her master.

Concerned about the physical toll the second trial took on Sam, Dean benches his brother from hunting until he heals up. So, when geektastic hacker Charlie stumbles upon a case and finds the boys, Dean decides it's time to teach Charlie how to be a hunter-in-training. While happy to see "her highness," the boys suspect Charlie is hiding something; a secret that could get her killed.

With some help from Charlie, Sam and Dean inadvertently release two individuals contained inside of the Men of Letters bunker: an evil witch, and a young woman, both imprisoned since 1935. They soon discover that the woman is Dorothy of Oz, and she is hot on the trail of the Wicked Witch, who plans to summon her evil army to Earth and conquer the planet.

Sam is scanning the internet for suspicious paranormal activity and comes across a video of Charlie beating up a district attorney. Dean suspects she’s back from Oz and hunting on her own, assuming the district attorney must have been a demon. When they do find Charlie, they are shocked when she tells them why she really came back from Oz.

Charlie calls Sam and Dean to tell them she found the Book of the Dead which could help remove the Mark of Cain. The Winchesters race to her after she tells them she’s been shot by a man named Jacob Styne who says the book belongs to his family and he won’t rest until he gets it back. Castiel and Metatron take a road trip to find Castiel’s grace but they hit a couple road bumps along the way.

Dean and Sam investigate a bizarre murder and realize the killer bears the same tattoo as those from the Styne family. Eldon Styne attacks Dean and a brutal fight ensues. Meanwhile, Castiel acts as referee when Charlie and Rowena are forced to work together on the Book of the Damned. Crowley discovers his mother is missing and knows she's up to something so he turns to an old enemy for help.

Lucifer rules over heaven but things aren’t going exactly as planned, exasperating his first lady, Jo. Sam and Castiel are perplexed by the return of Gabriel. Meanwhile, Dean gets one step closer to finding Mary and Jack.

Sam and Dean devise a plan that will save innocent lives. Meanwhile, Jack continues to wrestle with the consequences of his decisions.

After a hunt gone wrong leaves Maggie’s whereabouts unknown, Sam, Dean, Mary and Bobby race to find her, but what they find are their own worst nightmares.

Sam and Charlie team up to get to the bottom of a string of random disappearances. Meanwhile, Jack believes that he has found a case and convinces Dean to partner-up with him on the hunt.

With the plan in full motion, Sam, Dean, Castiel and Jack fight for the good of the common goal.