As Sam, Dean, and Castiel try to deal with the ramifications of Chuck's actions, they form a tentative alliance with a demon who reveals that the situation is direr than they think.
With the escaped souls wreaking havoc on Earth, Sam and Dean encounter a familiar face who reveals yet another of Chuck's lies. Sam's attempt to kill Chuck is revealed to have done more damage than originally thought.
Castiel embarks on a dangerous journey in a desperate attempt to find a way to close the rupture. Rowena resorts to drastic measures in order to save everyone. Old wounds make tensions rise between Dean and Castiel.
Plagued by dark nightmares, Sam adopts a cynical view of their mission as he joins Dean in investigating a murder and a kidnapping. Chuck starts plotting his revenge on the Winchesters.
The Winchesters' newest case brings them across a familiar face, who reveals dark prospects for their future. Sam realizes the source of his disturbing nightmares and what they mean.
Sam and Dean do their best to help when the ghost of an old friend seeks protection from a dark fate. Castiel investigates a case that inspires him to return to his original mission of helping people.
Castiel comes up with a risky plan in an attempt to exploit Sam's connection to Chuck to get more information. Dean runs into an old acquaintance, but the meeting quickly turns south as a disturbing truth comes to light.
While looking for a clue from Metatron's notes, Dean and Castiel come face-to-face with Michael. Sam and Eileen team up on a case that has unexpected ties.
With Sam and Eileen under Chuck's control, Sam is forced to confront the fact that they may be fighting a losing war. Dean and Castiel reach an accord while on a dangerous mission.
As they come to the realization that Chuck may have been bolstering their abilities all that time, Sam and Dean end up in a dangerous confrontation, forcing them to seek a way to regain their abilities so that they could beat Chuck.
As the Winchesters take a risky gamble in an attempt to win back their luck, Castiel's investigation of murder reveals a shocking return.
As Chuck starts implementing his plan to destroy various worlds, the Winchesters race to save an old friend before she goes down with one of the worlds. Billie reveals that she knows more about Chuck's fate than she has been letting on.
In an attempt to find an object that may help them against Chuck, Castiel makes a daring journey that brings him face-to-face with an old foe. Jack deals with the consequences of an unexpected trip to the Garden of Eden.
The discovery of a wood nymph that used to work for the Men of Letters leaves Sam and Dean with the realization that they need to appreciate the little things in life before it's too late.
As the Winchesters find out more about Chuck and Amara's history, Jack reveals the disturbing details of Billi's plan to get rid of Chuck, prompting Castiel to go on a journey to find an alternative.
Sam and Dean are drawn back into an old case after a childhood friend gets killed. Billie reveals that their time is up and the confrontation with Chuck is imminent.
With time running out, Jack undergoes one last test to prepare himself to take down Chuck. Sam makes a shocking discovery about Billie, as Chuck tries to turn the Winchester brothers against each other.
As the Winchesters and Castiel fend off attacks from Billie, Chuck wreaks havoc on the world. Castiel makes a shocking declaration as he prepares to make the ultimate sacrifice for Dean's sake.
Surrounded by nothing but death and despair, the Winchesters make unlikely alliances in one last attempt to bring Chuck down.
As the Winchesters investigate an old case of their father's, the brothers' final outing as hunters ends on a tragic note.