A Little Slice of Kevin is the 7th episode of Season 8. It aired on November 14, 2012.
Sam and Dean are stunned when Castiel suddenly appears back on Earth with no memory of how he escaped from Purgatory. Meanwhile, Mrs. Tran hires a witch to concoct a demon bomb, but the witch double crosses Mrs. Tran and turns her and Kevin over to Crowley.
Dean is driving in the Impala and thinks he sees Castiel walking on the side of the road. He hits the brakes and backs up, but the angel isn't there. He arrives back at Rufus's cabin, and Sam asks him what's wrong. Dean says he's fine, and Sam tells him about a boy named Aaron Webber going missing from a playground just as a surprise tornado hit. There have been other disappearances that corresponded with freak weather phenomena in the last few weeks, but the victims don't have anything in common. The brothers decide to investigate the possibility that Demons are behind the kidnappings.
Indeed, Crowley is behind the disappearances. He has been torturing Samandriel with an Angel Blade, making him give up names. When Samandriel tells him that there are no more names because "the next generation isn't born yet," Crowley stops torturing him and goes to speak with the people his demons have kidnapped, among them Aaron.
Meanwhile, Kevin Tran and his mother Linda Tran have been hiding in an abandoned diner set up with demon booby traps, salt lines, and hex bags. Linda tells Kevin that she wants to go on the offensive by building demon-killing bombs. She found a Witch named Delta Mendota on Craigslist and hired her to gather the ingredients they need for the spell Kevin used to kill Crowley's demons. Kevin isn't sure they can trust her, but Linda says that Delta doesn't know the actual spell, and she should have everything they need soon.
In Salina, Kansas, Dean and Sam question Mrs. Hagar, the last person to see Aaron before the tornado hit. She tells them that she doesn't remember anything between taking Aaron to the bathroom and waking up in a park three blocks away. She doesn't react when Sam starts to mumble an exorcism under his breath; however, she says that it smelled like sulfur when she woke up. They're almost certain that demons have Aaron now, but aren't sure why.
That night as Sam sleeps, Dean reads through the missing persons reports on their laptop. When lightening flashes, he looks up at the window and sees Castiel standing outside, looking in, but in an instant he's gone. Dean goes to the window, and Sam wakes up and asks him what's wrong. Dean tells him that he thought he saw Castiel just now and earlier on the road. He feels terrible that he couldn't pull Castiel out of Purgatory and doesn't understand why Castiel didn't try harder to escape. Sam says that Dean likely has survivors guilt and that he needs to get past it. Dean remembers a moment in Purgatory when Castiel had said that if he couldn't get out, he wanted to thank Dean for everything he'd done. Dean had told him that no one would be left behind.
The next morning, Crowley asks the people he's kidnapped if they can read the God tablet. They're confused and some of them ask Crowley if they're on an alien spaceship. When one of the abductees, Dennis Adams, starts to complain about his rights, Crowley kills him with a hand gesture. One of the women, Krista, nervously tries to read the tablet, but when she starts reciting the Declaration of Independence, Crowley realizes they will be no help.
Back in Salina, Sam has found another person who went missing during a strange weather phenomenon: Luigi Ponzi in Rome. He's telling Dean about it when Castiel appears in their motel room. Shocked, the brothers ask him how he escaped Purgatory. Castiel says he doesn't know - he just appeared on the side of the road in Illinois and has been trying to reach them since. He's not at full power, though, and he goes to take a shower. Dean remembers the moment they found the way out of Purgatory and he performed the ritual to take Benny's soul into his arm. He and Castiel had been heading for the portal when Leviathans had appeared to attack them. While Castiel is in the bathroom, Dean tells Sam that he's not sure he believes Castiel's story because he remembers every moment of Purgatory, and considering the shape Castiel was in, someone or something must have pulled him out.
Meanwhile, Delta shows up at the Tran's hideout with the ingredients for the demon-killing bombs. After Linda sprays her with holy water, she goes to the bathroom. When she gets back, Linda asks her why she only brought enough stuff to build one bomb. Delta tells them they need to pay her now if they want more, and Linda, angry, tells Kevin to get her purse. Too late, Kevin notices that Delta broke the salt line in front of one of the windows, and Crowley appears in the room with another demon. Delta made a deal with him, and he banishes her by snapping his fingers, tells the other demon to kill Linda, and disappears with Kevin. Linda grabs her water gun and starts soaking the demon with holy water.
Sam tells Dean that there haven't been anymore freak disappearances and lists the names of the seven people who have vanished. Castiel joins in the recitation, and they ask him how he knows who's gone missing. He tells them that they are all future Prophets. Only one prophet can exist at a time, though, so Chuck must be dead and one of the others will only become the prophet after Kevin dies. Sam and Dean realize that Crowley must be holding the others as "insurance" while he looks for Kevin, and then Sam gets a call from Linda: Crowley has Kevin, and she needs their help.
They drive to a meeting point and, as they wait for Linda, Dean remembers the moment he escaped Purgatory. Leviathans had attacked just as he and Castiel were climbing to the portal, and they beat on Castiel heavily before Dean could decapitate them. They then continued upwards, but Castiel fell behind and Dean, straddling the divide, had tried to pull him through. The last thing he remembers from Purgatory was Castiel calling out his name as his hand slipped free from Dean's grip. Dean shakes free from the memory and tells Castiel that he wants to talk to him outside the Impala. Once out of Sam's earshot, he asks Castiel what happened in Purgatory. He felt like Castiel just gave up and didn't believe that Dean could save them, and he tells Castiel emphatically that he did everything he could - he did not leave him. Confused, Castiel asks Dean if he thinks it was his fault. Before Dean can answer, Linda arrives.
Linda gives Kevin's notes to Sam. They ask her what happened, and she admits to hiring a witch who sold them out to Crowley. Fortunately, she was able to capture the demon Crowley left behind to kill her, and he's in the trunk of her car under a devil's trap. Dean unsheathes Ruby's knife so he can torture him for Crowley's location. Meanwhile, Crowley is trying to convince Kevin to cooperate with him. He introduces Kevin to the other prophets and tells him that if he dies, he will just be replaced. When Kevin hesitates, Crowley kills Krista, spraying her blood everywhere with the snap of his fingers. He then straps Kevin into the same chair that Samandriel was tortured in and cuts off his left pinky finger. Kevin screams in pain and finally agrees to help Crowley. He starts reading the tablet slowly, but Crowley quickly becomes bored and tells him to get to the big stuff.
Dean and Castiel along with Linda and Sam drive up to an abandoned factory in Atlantic, Iowa. Dean checks with the captive demon that they're in the right place and then kills him. Sam handcuffs Linda to her car's steering wheel so that she won't get near Crowley, and then heads inside, where the men split up. Alone, Sam surprises four demons with Linda's demon-killing bomb and then finds and helps the remaining five prophets escape. Dean and Castiel go further into the factory, and as Castiel struggles to kill the low-level demons they encounter, Dean realizes that he's still weak from Purgatory.
As Dean and Castiel get closer, Kevin continues reading the tablet. He tells Crowley that there is information on how to kill demons and how to close the gates of Hell. There is also a personal note from the writer of the tablet, God's scribe Metatron, saying that after completing this series of tablets he is taking his leave of his master in this world. Just as Crowley is asking Kevin if that means there are tablets other than the Demon and Leviathan tablets, Dean and Castiel find the door that Crowley and Kevin are behind. Dean can't pick the lock, so Castiel zaps inside alone.
Crowley is surprised to see Castiel, and when Castiel pulls out his angel blade, he pulls out his own. Kevin gets out of the way as Crowley and Castiel face off across the tablet. Crowley tells Castiel that he knows he's drained, but Castiel refuses to admit to any weakness. He glows with heavenly light and the shadows of his wings appear on the wall behind him. When Crowley tries to grab the tablet and run, Castiel smashes it and the table it was on. Crowley vanishes with half of the tablet in his hand, and Castiel collapses just as Dean bursts into the room.
Afterwards, Kevin is more determined than ever to close the gates of hell. Sam tells him and Linda that they can stay with Garth in the meantime. While they talk, Dean confronts Castiel about his recklessness going against Crowley alone. Castiel says that Dean is not responsible for everything, and especially not for Castiel being left behind in Purgatory. He touches Dean's forehead to make him relive the moment he escaped Purgatory so that he can see what really happened. Dean didn't lose his grip on Castiel's hand: Castiel pushed him away and told him to go. Castiel wanted to stay in Purgatory to do penance for the terrible things he'd done, and he had planned to stay all along. He finishes by telling Dean that he can't save everyone.
Sam comes over to plan their next steps, and Castiel all of a sudden finds himself in a mostly white room standing in front of a woman at a desk. He asks her where he is, and she says that he's in a part of Heaven not many have seen. She introduces herself as Naomi and tells Castiel that he was rescued from Purgatory by angels so that he could help Sam and Dean and report to her about their activities. Castiel refuses to spy on the Winchesters, but is unable to resist telling her what she wants to know when she asks him. She also tells him that he won't remember their conversations and that no one, including himself, will notice that he's been gone. In the next instant, he is back standing with Sam and Dean, agreeing to help them look for the other half of the Demon tablet that Crowley holds.
Dean: Oh well, Purgatory will do that to you.