|“||I'm not going back. (...) I fought beside these people. I respect them. I respect their cause. You can't expect me to just abandon them. (...) Sam. Dean. I know what you went through to come find me. But these people are being slaughtered. They need me here.||”|
|“||I think Mom made up her mind. (...) Mom doesn't want to leave these people, so let's take them with us. (...) I'm not saying abandon the fight. I'm saying get them somewhere safe and then we all find a way to take down Michael. Then once we do, they can come back and save their world.||”|
|“||So let me get this straight. You want us to follow you through a magic door that's gonna blast us the hell out of here and into some kind of fairy tale world where everything's pretty? (...) Nobody here is running out on our buddies, running out on the fight.||”|
|“||My brother and I... back home, we're sitting on the biggest collection of lore and -- and weapons in our world. Now something in there, it -- it might be enough to even the odds. (...) So we find that, then you come back here with a plan, a plan to beat Michael and his armies. And then you win. (...) Exactly. You might think you don't know us but you do. We've been where you are. Hell, we are you.||”|
|“||Got some news. We took a vote, see who was idjit enough to go off to this "Other Earth" with you. (...) Everyone. Me included. Whatever reason, I got a good feeling about you two.||”|
In an attempt to stop the archangel Lucifer once and for all, the Winchesters, Castiel and Crowley work together to lock Lucifer in an alternate reality called Apocalypse World. Though they succeed in trapping Lucifer, Crowley and Castiel die and Mary Winchester is trapped in Apocalypse World with Lucifer.
After being trapped, Mary and Lucifer are eventually captured by the Apocalypse World version of the archangel Michael. Learning of the Main Universe from Lucifer's mind, Michael attempts to have the Prophet Kevin Tran open a rift for him to lead his armies through. The ritual Kevin uses gives Lucifer the chance to escape back to the Main Universe, his grace partially extracted to power the ritual. The rift closes behind Lucifer, the ritual only powerful enough to send one person through before the rift closes again. Following his escape, Lucifer warns the resurrected Castiel of the approaching threat of Michael shortly before they are captured by the Prince of Hell Asmodeus.
After accidentally killing a human, Lucifer's Nephilim son Jack sets out to try to rescue Mary, eventually learning of her captivity by Michael while using dreamwalker Derek Swan in an attempt to open a rift between universes. After being found by the Winchesters, Jack shares the vision he saw of Mary with them, but the subsequent attempt to open a rift to Apocalypse World results in Jack being transported alone to Apocalypse World while the Winchesters are sent to the Bad Place. After some time in Michael's captivity, Jack escapes with Mary and links up with some of the surviving human population of Apocalypse World led by Bobby Singer. Following an attack by Zachariah, Jack and Mary begin leading a resistance against Michael to kill him and save what is left of humanity in Apocalypse World.
Following his escape from Asmodeus, Castiel informs the Winchesters of what he has learned from Lucifer about the events in Apocalypse World, including about the ritual Kevin used from the Angel Tablet to open the rift that Lucifer returned through. In hopes of finding a way to open a rift themselves and save Mary and Jack, the Winchesters enlist Prophet Donatello Redfield to search the Demon Tablet for a similar ritual. Despite Donatello being corrupted by the power of the Demon Tablet in his soulless state, the Winchesters and Castiel are able to get the ritual and quickly begin gathering the ingredients. A subsequent incursion into Apocalypse World by Dean and Arthur Ketch leads to the rescue of resistance member Charlie Bradbury and Arthur staying behind to find Mary and Jack and aid the resistance until Dean can return with reinforcements.
After getting Gabriel to join them, the Winchesters, Castiel and the witch Rowena MacLeod attempt to open the rift, only to discover that Gabriel doesn't have enough grace to perform the ritual. In an effort to both open the rift and power it long enough to complete their mission, the group captures Lucifer and uses him as a continuous power source for the ritual. However, Lucifer eventually breaks his bindings and is accidentally blasted through the rift to Apocalypse World where, after linking up with two teenage hunters, Sam is killed by a vampire on the way to the resistance outpost. Sam is resurrected by Lucifer who asks for Sam's help in bonding with Jack in exchange. Sam reluctantly leads Lucifer to the outpost where the Winchesters are reunited and Lucifer, allowing himself to be bound by the Supernatural Handcuffs, reveals that they have roughly thirty-one hours before the grace he left behind runs out and the rift closes again.
With only thirty-one hours left, Sam and Dean approach their mother to return to the rift and the Main Universe. However, despite recognizing all that her sons have gone through to find her, Mary refuses because she feels that the people of Apocalypse World need her more with Michael and his angels slaughtering them. Recognizing that Mary won't change her mind, Sam proposes evacuating everyone through the rift to safety until they can find a way to defeat Michael and then return. Mary is touched by their offer and tells her sons that they have twenty-five people that would need to be evacuated. Dean warns Mary that getting twenty-five more people to the rift may not be possible before they are interrupted by Castiel.
At the same time, after remembering his mother's message to him and the things he has done, Jack agrees to hear Lucifer out despite Castiel's warnings. Lucifer claims that despite everything humanity has tried to put on him, most of the evil that has happened is just human nature, pointing out that he was locked in Lucifer's Cage for millennia by God.
As Castiel leaves to warn the Winchesters, Lucifer claims to want a chance to better himself from his past and talks about how the two of them are the members of the most powerful family in history before being interrupted by Dean. Jack admits to being interested in learning more from Lucifer about his powers and family and rebuffs their attempts to talk him out of speaking with Lucifer, calling Lucifer his father.
A short time after the argument, the resistance force departs the outpost in order to link up with the rest of the resistance at their base camp. Mary urges Dean to go easy on Jack who has been fighting a war and has lost people that he cares about. Mary also urges Dean to allow Jack to get to know Lucifer and see who Lucifer truly is for himself rather than through how Dean sees him, assuring Dean that Lucifer won't be able to corrupt Jack to evil. At the same time, Jack tells Sam that he has been suggesting to Lucifer that with the two of them there, they can finally kill Michael and end the war. However, Sam discourages Jack from the idea as that is not the point of their mission.
As the group walks, they encounter Castiel who warns that he can't find Gabriel who went ahead to scout the route ahead and should already be back. Gabriel runs up warning of approaching angels. As the resistance fighters ready their weapons, six angels arrive and prepare to attack. Before they can, the angels are suddenly combusted to dust by Lucifer who melts his handcuffs. Lucifer reveals that he was faking being effected by the handcuffs all along to make them feel better and uses his killing the angels as proof that he is a team player.
At the resistance base camp, the Winchesters are disconcerted to discover that it is the Apocalypse World version of Singer Auto Salvage, albeit not in Sioux Falls like their Bobby's. The two are warmly greeted by Bobby Singer with whom they joke about the differences between him and their Bobby. Bobby tells them that Charlie Bradbury and Arthur Ketch are off on a mission chasing an angel kill squad out to execute some resistance members. Bobby admits that he's heard about their idea to take everyone to the Main Universe, but finds it to be a stupid idea.
As the Winchesters talk with Bobby, Lucifer and Jack continue their conversation with Lucifer explaining their family to Jack. Lucifer introduces Jack to his uncle Gabriel who is less than pleased to see Lucifer following Lucifer's attempt to kill him years before. As Lucifer tries to get Gabriel to back him up in telling Jack how awful their father was to them, Gabriel snaps at Lucifer that Lucifer is not a victim and it has always just been Lucifer's excuse "for it all" before walking away while leaving Jack confused.
In the command tent, the Winchesters make their pitch for the exodus to Andy and two other resistance higher-ups who are dubious at the idea. Sam and Dean argue that they have the biggest collection of lore and weapons in their world and it could hold the key to finding a way to defeating Michael and coming back later with a better plan to win. Andy and the other leaders eventually agree to talk to their people and take a vote on the idea to see who will be willing to go. After the three leave, the Winchesters are informed by Bobby that Arthur and Charlie been captured.
As the Winchesters and Jack leave to rescue Arthur and Charlie, they leave Gabriel and Lucifer behind to guard the base in case of any angel attack. Gabriel recognizes that Lucifer is annoyed that he can't take the time to impress Jack and taunts him about it. Though Lucifer believes that he can influence Jack over to his way of thinking, Gabriel doesn't think Jack will want that as his mother's bloodline and the Winchesters' influence is too strong upon him. Fed up with Lucifer's claims of changing and blaming everything on God, Gabriel angrily confronts his brother over the real reason God locked Lucifer up, to protect humanity from Lucifer's evil and jealousy, reducing Lucifer to tears.
After the successful rescue of Charlie and Arthur, the Winchesters return to the base camp where Bobby congratulates them on the win. Bobby reveals that the vote is in and everyone, Bobby included, has decided to join the exodus to the Main Universe. Though pleased, the Winchesters realize that they have a practical problem in that they need to find a way to get everyone to the rift and they only have a few hours until it closes again. Spotting an old bus nearby, Dean questions Bobby about it. Over the next couple of hours, Dean works on repairing the bus and eventually manages to get it fixed with Lucifer's help by daylight.
With the bus running, Gabriel is surprised to realize that Dean intends to let Lucifer drive, but Dean figures that it will at least keep Lucifer in one place and Castiel can keep an eye on him. With an hour and fifty-seven minutes left, everyone begins boarding the bus, but Sam spots Jack heading off on his own. Joined by Lucifer, Sam goes to talk to Jack who is still determined to keep his promise to kill Michael despite their mission to get everyone to the rift and the dangers he will face. Lucifer sides with Sam on the issue, reminding Jack that Michael is not easy to beat and Jack trying and potentially getting caught will put everyone else in danger if they have to mount a rescue mission for him. Jack finally acknowledges that his father is right and joins everyone else.
With Dean, Sam, Jack and Gabriel leading the way in a jeep, the exodus begins to the rift between the worlds. Arriving at the rift, it is discovered to be on the verge of closing, but Rowena begins performing a spell using power from the Black Grimoire that stabilizes the rift and buys them more time. Though shocked by the development, Sam orders everyone through the rift led by Arthur and Castiel to show the others how. As Rowena holds the rift open, Arthur, Castiel, Jack, Mary and the people of Apocalypse World begin passing through into the Men of Letters bunker, but Sam holds Lucifer back, telling Lucifer that they need him and Gabriel to stay back and guard the rift in case of something going wrong.
After most everyone is through the rift, Michael suddenly flies in in the form of an angelic comet, his explosive landing killing Andy and two other hunters. Lucifer confronts Michael and hits him with an energy blast, knocking Michael back slightly, but otherwise leaving him unharmed. Michael returns fire with two energy blasts of his own, knocking Lucifer to the ground and severely weakening him.
Turning his attention to Gabriel, Michael is surprised to recognize his brother. Gabriel orders the Winchesters, the last ones left, to go while he buys them some time. Despite their objections, Gabriel chooses to fight instead of running as he has always done in the past. Both Gabriel and Michael draw archangel blades and engage in hand-to-hand combat. Though Gabriel lands a hit on Michael, he proves to be no match for the stronger archangel. Michael quickly overpowers Gabriel and stabs him in the abdomen with his archangel blade, killing Gabriel to Sam and Dean's horror.
With Michael distracted laying Gabriel's dead vessel down on the ground, Dean quickly heads through the rift at Sam's urging. Before Sam goes through, he realizes that the weakened Lucifer is trying to follow him and physically restrains him with Lucifer too weak to shake off Sam's hold. Though Lucifer begs Sam to let him go as he's wounded, Sam asks how Lucifer thought it would end and shoves the weakened archangel to the ground. As Michael turns his attention to Sam, Sam enters the rift. Michael races to the rift, but the rift closes before he can reach it, trapping Lucifer and Michael in Apocalypse World.
After reaching safety in the Main Universe, the refugees from Apocalypse World celebrate their newfound safety and freedom, though Bobby vows that someday they will return to their world and free everyone that is left. With the help of the Winchesters, the refugees begin to settle in to the Main Universe and Bobby later tells Mary that many of the refugees will likely not return even if they can get the rift open again, Bobby included.
After being trapped in Apocalypse World, Lucifer offers Michael a deal where he will share the ritual to reopen the rift in exchange for Michael allowing him to take Jack when they reach the Main Universe while Michael will be allowed to conquer everything else. The deal between the two archangels results in them successfully reaching the Main Universe where Lucifer steals Jack's grace and becomes super-charged after Jack discovers his father's true nature and turns on him. In order to battle Lucifer, Dean becomes Michael's vessel, enabling Dean to finally kill Lucifer. However, as a consequence, Michael is left loose upon the Main Universe in the body of his true vessel.
- This conflict is the first time that Lucifer is on the same side as the Winchesters since the Second War against the Darkness, albeit to get close to Jack.
- Part of this conflict occurs at the same time as the Capture of Arthur and Charlie.
- Sam and Dean succeed in rescuing Mary Winchester and Jack from Apocalypse World, their driving goal throughout Season 13. During the exodus through the rift, the Winchesters send Mary and Jack through as two of the first people to go to the Main Universe.
- The people evacuated during the exodus are the only surviving beings from Apocalypse World as it was subsequently destroyed by God.