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.
While Sam and Dean help Castiel interrogate one of Metatron's angels, Abaddon takes extreme measures to force Crowley to help her against the Winchesters.
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
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.
Jones takes the leadership position from Amanda at The Shop, then calls Nikita and offers her and her team complete freedom by wiping away their identities and faking their deaths if they drop their mission. The team lands on a secluded Pakistan air strip, but a local drug czar and his men storm the plane and demand ten million dollars, and Nikita turns to Alex for the money. Alex removes some diamonds from a safe deposit box to make the payment, and Sam sees an opportunity to recoup his losses and considers stealing the diamonds. Meanwhile, Michael comes face-to-face with an old rival, Ramon, who hits Michael with some hard truth.moreless
Relations between the U.S. and Pakistan continue to deteriorate after Amanda plants evidence suggesting that Pakistan hired Nikita to assassinate the President. Ryan becomes increasingly suspicious of Birkhoff’s recent odd behavior and tells Nikita and Michael that he thinks Amanda may have kidnapped Birkhoff and replaced him with a double. An NSA official, Ronald Peller, gets under Birkhoff’s skin. Meanwhile, the CIA captures Alex and questions her about her involvement with Nikita.moreless
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
Nikita rejoins Michael, Birkhoff, and Ryan on the team’s aircraft command center. Michael refuses to discuss their relationship but tells Nikita to remain with the group until they can help her clear her name. Ryan discovers that Amanda is making doubles of important people with The Shop’s help. Nikita learns that one of Amanda's doubles has replaced the Director of the FBI, but she doesn’t know how to kill him without exposing herself. Meanwhile, Alex holds Sam at gunpoint and demands he return what he stole from her, but the two have to work togethe to escape an attack by a gang of thugs.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
Nikita is still on the run after she was framed for the assassination of the President of the United States. Dale, an ENN news reporter, starts to question what really happened the night of the assassination. Nikita, seeing this as a potential opportunity to clear her name, re-enters the U.S. to talk to Dale but walks right into one of Amanda's traps. Nikita's team is alerted of the problem, and Michael works to track down Nikita before Amanda finds her. While Birkhoff and Ryan assist Michael from their new mobile office, a high-tech aircraft, Alex stakes out a human-trafficking ring and discovers that The Shop is involved. She runs into trouble, and Alex is shocked when Owen/Sam arrives at the scene.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
Amanda places Nikita in a life-threatening situation where she has to choose between saving Michael or saving her own life. The team works to find a way to stop Amanda, but with Division diminished, they struggle to stop her plan.moreless