At an outdoor pre-school, one of the teachers, Miss Hagar, takes Aaron to the nearby restroom to clean up. As she goes in with him, her eyes glow black. A golden light fills the cubicle and outside a miniature tornado forms. As the children and teachers run inside, the restroom door blows upon, revealing no one inside.
Dean is driving back to the motel with food when he passes Castiel on the side of the road. Surprised, Dean turns and backs up but there's no sign of his friend. He continues onto the cabin and Sam notices that his brother appears distracted. Dean dismisses what he saw as his imagination and Sam explains that he's picked up on reports of people disappearing. In each case, some strange natural phenomena accompanied the disappearances. None of the victims have anything in common and the brothers head out to check the nearest disappearance at the pre-school.
Crowley captures and tortures the angel Alfie, who insists that he's already given the demon all of the names. When the angel warns that his fellow angels will come looking for him, Crowley points out that they're too busy to worry about one missing angel. Alfie insists that the next generation hasn't been born yet and Crowley realizes that he's telling the truth. He tortures the angel a bit more for fun and then goes to a nearby room where the missing people have been gathered around a table.
Kevin comes back to the abandoned restaurant where he and his mother have holed up. Linda douses him with holy water and then says that they have to stop running and take some action. She explains that she plans to make more demon-killing bombs like the one that Kevin used against Crowley's demons. When Kevin points out that it took weeks to gather the ingredients from around the world, Linda explains that she contacted a witch on Craigslist and has her assembling the past. She's been careful to make sure that the witch, Delta Mendota, doesn't know how the components need to be assembled. Delta checks in with them via Skype and says that she has most of what the Trans need. She asks about the recipe but Linda reminds Delta that isn't part of the deal.
Sam and Dean pose as FBI agents and talk to Miss Hagar, who doesn't remember anything of what happened. Sam mutters an exorcism but nothing happens, while Miss Hagar admits that she smelled sulfur when she realized that Aaron was missing. The brothers go back to the motel and Dean tries to sleep. As he glances up at the window, he sees what appears to be Castiel and goes to look. There's nothing there and Sam wakes up and asks what the matter is. Dean tells his brother what he saw but Sam reminds him that Castiel couldn't have come back. He tells Dean not to let it eat him up and goes back to bed.
Dean, Castiel, and Benny head for the portal. Castiel continues to doubt that it's there or that he will be able to pass through, and Benny insists that "they" promised it would work. As they continue on, Castiel takes the opportunity to thank Dean for everything that he's done.
Crowley's abductees think that he's an alien and that they've been abducted for experiments. He shows them the Word of God tablet and tells them to translate it, but none of them can. One man tries to leave and Crowley makes him choke on his own blood until he passes out. Another woman tries to translate it but isn't even close to getting it right.
Delta comes to the restaurant to meet with the Trans. Once Linda confirms she isn't demon-possessed, Delta informs her that she only brought part of what they need. She refuses to turn over the rest until she's paid in full.
As Dean washes up, Sam checks the Internet and confirms that people have disappeared all over the world. Castiel appears behind Dean and greets him. The brothers question Castiel, who explains that he doesn't have his full power and that he couldn't reach out to them until now. When Dean asks how he made it out of Purgatory, the angel admits that he doesn't remember. The last thing he remembers is hiding from the Leviathans in Purgatory, and then he found himself on the road.
The three fugitives approach the portal and it manifests, reacting to Dean's presence. Dean and Benny cut their arms and merge their blood, and Benny's soul is sucked into Dean's body. Dean and Castiel climb up toward the portal only for two Leviathans to arrive.
After Castiel goes to the bathroom to clean up, Dean tells Sam that he remembers everything that happened in Purgatory and that he doesn't believe that Castiel could have forgotten. He's also sure that Castiel couldn't have gotten out on his own. As Sam wonders what did rescue Castiel, Castiel comes out, back to his old self.
After using the bathroom, Delta comes back and Linda reluctantly agrees to pay first before getting the ingredients. As Kevin goes to the storeroom to get his mother's purse, he discovers that someone has broken the salt line in front of a window. He runs back as Crowley and his assistant demon teleport in. Crowley congratulates Delta on betraying the Trans and then teleports the witch away when she gets cocky. Linda offers herself in lieu of her son but Crowley says she's useless to him. He tells his assistant to dispose of her and clean up, and then teleports away with Kevin. Linda grabs a super-soaker filled with holy water and sprays the demon before he can do anything.
Sam informs his brother that the abductions have stopped and mentions the seven people that disappeared. Castiel recites the names along with him and explains that they're future prophets: Kevin's successors for when he dies. As one prophet dies, the next one becomes active. Every angel knows the name of all past, present, and future prophets, and Castiel concludes that Chuck is dead, activating Kevin. They realize that Crowley must have found out the names of the prophets from an angel. Before they can pursue the matter, Linda calls Sam to tell him what's happened.
Crowley takes Kevin to the refinery where he's keeping the future prophets. Kevin refuses to talk, realizing that Crowley will kill him regardless, and Crowley levitates one of the other prophets into the air and then makes him explode as an object lesson.
The Winchesters and Castiel drive to the rendezvous point. As Dean waits, he looks out the window.
The Leviathans knock Dean down the hill and attack Castiel, who manages to hold them off until Dean can decapitate them. The portal starts to close and Dean steps into the portal. He reaches for Castiel's hand but is unable to hold on and the angels slides backward.
Dean talks to Castiel privately and asks why he came up. As Castiel realizes that Dean is blaming himself, Linda arrives and tells them what happened. She gives them her son's notes and shows them the captive demon in the trunk of her car. Dean takes out the demon-killing knife and prepares to convince the demon to tell them where they can find Kevin.
Crowley straps Kevin into a chair in a separate room and gives him one last chance to cooperate. When Kevin refuses, Crowley cuts off one of his fingers and the prophet finally gives in. He begins translating starting at the beginning, but Crowley tells him to skip to the important stuff.
The brothers and Linda drive to the oil refinery. Before they go in, Sam handcuffs Linda to the steering wheel so she can't get in, get captured, and get used as a hostage. Dean kills the demon and they head in.
Kevin reads about anti-demon weapons and sealing the gates of Hell, and Crowley figures that he can't let the table get into human hands. The prophet finally finds an entry from the archangel Metatron, the scribe of God, which consists of a farewell note.
Sam splits up to find the abducted prophets while Dean and Castiel track down Kevin. Three demons come at Sam but he used a demon bomb to kill them.
A demon attacks Dean and casts him aside. Castiel grabs the demon and kills him with a touch, but staggers back as Dean realizes that his friend is still weakened.
Kevin finishes reading the note, which reveals that there is a compendium of tablets.
Dean tries to pick the lock to Kevin's cell door. Impatient, Castiel teleports in and confronts Crowley. He draws his heavenly knife but Crowley draws his own knife, realizing that the angel is weakened. Castiel says that he still has enough to deal with the demon and manifests in all of his glory. Crowley figures that Castiel can't maintain that level of power for long but refuses to take the chance. He grabs the tablet but Castiel smashes it in half. Crowley teleports away with one piece while Castiel holds onto the other.
Sam and Dean call in the police to take the surviving prophets home, while Sam tells Linda and Kevin that he's made arrangements with Garth to look after them. Meanwhile, Dean tells Castiel that he screwed up. Castiel tells Dean that he doesn't have to do everything, and that it wasn't his responsibility to bring Castiel out of Purgatory. Realizing that Dean blames himself, Castiel explains that Dean remembers it that way because he has to. He touches Dean's head and shows him what really happened...
As Dean reaches the portal and tries to pull Castiel through, Castiel deliberately lets go and slides back, telling Dean to move on.
Castiel explains that he didn't want to be saved because he had to penance for the crimes he committed in Heaven and Earth. He planned to stay in Purgatory all along but couldn't bring himself to tell Dean. The angel tells Dean that he can't save everyone as Sam comes over and asks if everything is okay. Castiel tells him that they've set a few things straight...
Castiel finds himself in a plain white office. An angel, Naomi, welcomes him home and introduces herself. She explains that her legion brought Castiel out of Purgatory although it cost many of them their lives. Naomi orders Castiel to tell her everything about the Winchesters and the angel, compelled against his will, tells Naomi the brothers' success at recovering the tablet. When he wonders why he spoke, Naomi tells him that he's to report in regularly and that he won't remember their meetings.
... and that now that Dean understands, he'll stay with them. The angel is briefly puzzled, thinking he forgot something, and walks off. Sam asks his brother if he's good with the angel and Dean looks suspiciously after his friend as he says that he is.