Dean falls increasingly under the spell of the First Blade. Meanwhile, Metatron makes his move against humanity, as Sam, Castiel, and Gadreel try to stop him.
Castiel calls on the Winchesters to help when his army of angel followers are attacked, and Dean is all too eager to help under the First Blade's influence.
In Chicago, Sam and Dean encounter five clans of monsters that run the city's underground... and Ennis, a young would-be hunter who seeks revenge on one of the clans.
Sam goes to check out a report of peaceful people transforming into violent killers and discovers a connection to a case involving his grandfather. Meanwhile, Dean deals with the aftermaths of acquiring the Mark of Cain and Crowley is eager to take advantage of his weakness.moreless
Crowley starts taking human blood again and Abaddon learns of his search for the First Blade. To find the Blade before the Knight of Hell does, Sam and Dean enlist the help of a former Man of Letters.moreless
Sam and Dean travel to Washington to investigate the death of a young girl, only to discover that Harry and Ed, the Ghostfacers, have arrived before them.
Crowley and a reluctant Dean go on a road trip to find The First Blade, the only weapon that kill their mutual enemy, Abaddon. Meanwhile, Castiel proposes to use Gadreel's remaining grace in Sam to track the angel, but warns that it could cause Sam permanent damage.moreless
In the wake of Kevin's death, Castiel proposes a plan to Dean to help Sam retake control of his body from Gadreel. However, they have to turn to Crowley for help.
Sam and Dean investigate an angel slaughter and discover that Castiel is already looking into the matter. The individual responsible captures Castiel, while Dean wonders whether ti's time to tell Sam the truth about Ezekiel.moreless
When four members of the same church chastity group disappear, Sheriff Jody Mills calls in Sam and Dean for help. However, Dean soon disappears and Sam and Jody have to go after him.moreless
A man named Sonny calls Dean for help, and Sam is surprised to learn that Sonny and Dean spent time together at a home for delinquent boys. Sonny needs help dealing with a ghost and the Winchesters agree to help investigate. Meanwhile, Dean links up with an old girlfriend from his time in the home.moreless
When Castiel calls the Winchesters about mysterious disappearances in his neighborhood, Dean is forced to keep Sam (and Ezekiel) away from Castiel by asking to help Kevin and Crowley decipher the tablet. Meanwhile, Crowley asks for one phone call to Hell in return for his cooperation.moreless
To solve two murders, Dean casts a spell to bond with the German Shepherd that witnessed both crimes. However, the spell has an... unfortunate side effect.
The Winchesters call Charlie in to help them with a Men of Letters computer, only to discover a strange green-webbed wall where they find a young woman named Dorothy inside Now they trio must join forces with Dorothy to stop the Wicked Witch from either returning to Oz or bringing Oz to the real world and wrecking havoc.moreless
Ezekiel warns the Winchesters that a group of disgruntled former angels are hunting their friend Castiel, and the brothers set out to find him before it's too late. Meanwhile, Castiel learns more about the human lifestyle.moreless
Dean has a surprise for Sam and Kevin: Crowley, locked up in the trunk of the Impala. While they try to track down the demons on Earth, Abaddon continues with her plan to rule Hell.moreless
Dean is devastated by the fact that the doctor tells him Sam won't make it, so he promises any angel willing to help that he will owe them a favor. Many angry angels want to find Dean and kill him, but Ezekiel gets to him first. At the same time, Sam is fighting for his life, and Castiel has a hard time surviving without his powers.moreless
Using the tablet half in his possession, Crowley prepares to make his final move in the grand game against Heaven. Only Dean, Sam, and Kevin can stop him. Meanwhile, Castiel and Metatron join forces and try to stop Naomi's scheme.moreless
Sam, Dean and Castiel are reunited and search the files of the Men of the Letters to find a film that could help them figure out the third trial. Meanwhile, Metatron asks for Castiel's advice about the problems in Heaven, and Crowley delves into the brothers' past... and some familiar facesmoreless
Sam and Dean receive a video message from Kevin which leads them to a casino in Colorado, where they find a mysterious recluse that might help them fill in the gaps in Kevin's research. At the same time, Crowley is winning at the tables. Meanwhile, Castiel tries to escape from Naomi and the other angels that are after him.moreless
Dean is concerned about the physical impact the second trial had on Sam, so he insists that Sam stop hunting for a while. When Charlie comes across a case and finds the boys, Dean decides it's time to teach her how to be a hunter. However, the boys suspect she is hiding something from them that could get her killed.moreless
Liam shares a terrible truth with Josh and Nora. More of Aidan's past is revealed as he deals with Kenny's transformation and Kat discovers a terrible secret.
Kevin calls in Sam and Dean when he hears Crowley inside of his mind. The brothers end up turning to Ajay, a Reaper, to help Sam with the second trial of the Tablet. Meanwhile, Naomi secretly visits Dean and gives him vital information, forcing him to seek out Benny's help.moreless
While Aidan waits for Kenny to wake up from his transformation, Josh and Nora prepare for their wedding. Meanwhile, Sally continues to deteriorate and fears that she will lose her soul to Donna.moreless