Sam's life hangs in the balance as Toni goes to drastic measures to get information from him. Dean comes face-to-face with an unexpected face from the past.
Dean reluctantly lets Mary join him as he goes to rescue Sam. Crowley comes up with a plan to entrap Lucifer in the Cage. Another member of the British Men of Letters makes an appearance.
The three Winchesters take a case that involves ghosts of children. Castiel makes an uneasy alliance with Crowley and Rowena. Mary confronts her feelings about the losses she suffered.
A mysterious death at a church leads the brothers to uncover the disturbing secrets of a religious family whose devotion put their own daughter's life on the line.
As Nazi necromancers attempt to bring Adolf Hitler back to life using one of his descendants and a pocket watch that holds his soul, the Winchesters race to put an end to the Nazi plan before it's too late.
The death of a legendary hunter brings fellow hunters from far and near to say goodbye. But when the gathered hunters start getting picked off one by one, it becomes clear that a malevolent demon is targeting their gathering.
Lucifer uses his latest vessel, a rock singer, to organize a concert with the aim of killing all the attendees. The Winchesters, Castiel, and Crowley struggle to find him before he exacts a bloody toll on the concert-goers.
When Lucifer possesses the president, the Winchesters find themselves in a bind as they try to find a way to exorcise him before he kills the president.
With the Winchester brothers incarcerated for trying to kill the president, Mary and Castiel are caught between managing the escalating supernatural activity, and saving the brothers.
A woman from Castiel's past comes seeking revenge on the angel for helping to destroy her family, forcing Castiel to confront the truth about the tragedy he participated in.
When Dean falls victim to a spell that takes his memory, Sam teams up with Rowena to find the witch family that cast the spell to save Dean's life.
When the Winchesters come up against a demon who recalls their old archnemesis Azazel, they come to learn that the Princes of Hell are after a familiar weapon.
Ketch encourages Mary to distance herself from her sons. The brothers' latest case leads them to Crowley's son, who is a man out of time. A Prince of Hell finds the pregnant Kelly.
As Mary and Ketch attempt to win over Sam and Dean respectively, a devastating attack by a nest of vampires leads Sam to make a decision behind Dean's back.
When a hellhound attacks a couple who hasn't sold their souls, Crowley discovers a plot to free Lucifer using his faithful hellhound. Sam comes clean about his collaboration with the British Men of Letters.
Mick joins the Winchester brothers on their latest case as they hunt for a werewolf, as they race against the clock to find the werewolf to save Claire Novack from turning into a werewolf herself.
Things come to a head between the Winchesters and the British Men of Letters after a mishap leaves one of the Men of Letters dead and Mick's mentor decides to eradicate all American hunters.
A missing person case leads the Winchesters to uncover a human sacrifice operation led by a local family. Ketch double-crosses the brothers and plants spy equipment in the Bunker.
As Sam tries to figure out a way to deal with Kelly's child without killing him or Kelly, Castiel secretly plots to kill the two, but an unexpected encounter changes his mind.
Sam and Dean help two siblings investigate the disappearance of their witch mother. Mary learns the truth about the British Men of Letters.
As Toni turns Mary into her puppet, Sam and Dean are tipped off that something is wrong when American hunters start dying in droves.
As the search for Castiel and Kelly heats up, Castiel comes up with a plan to defeat Lucifer using his own son's powers.
With war breaking out between the American hunters and the British Men of Letters, Dean enlists Toni's help to break Mary's thrall.