Crowley is interrogating the alpha shapeshifter, who has taken Crowley's shape. The king of Hell stabs the alpha in the chest with an iridium knife, but it still refuses to tell Crowley where he can find Purgatory. Finally, Crowley takes out a baby monitor and lets the alpha listen to the cries of all the baby shapeshifters it gathered, and threatens to kill them all unless it talks. When the alpha still refuse to tell him anything, Crowley decapitates it.
Dean and Sam turn over a captured Rugaru to two of Crowley's demons. When Dean asks when they'll meet Crowley again, the demons refuse to tell them anything and leave with their prisoner. Once they're alone, Dean complains about having to serve Crowley, but Sam says that it's the only way he can get his soul back. When Dean wonders if Sam wants his soul back, his brother notes that he's working with Crowley to do so. Before they can continue the discussion, demons arrive and ambush them.
When the brothers wake up, they discover that Meg has captured them. She wants to know where Crowley is, and threatens to torture them. However, Sam laughs and explains that Meg and her demons are Lucifer loyalists, and running scared because Crowley is hunting them down. Meg can't do anything to them, because she needs them to find Crowley. He suggests that they work together, surprising both Dean and Meg. In return for their help, Meg will torture Crowley for the information that Sam wants. She finally agrees and leaves them to get free on their own.
Once they're loose, Dean reminds Sam that Meg killed Ellen and Jo, but Sam figures that they'll kill Meg and her demons once they have the information on how to get Sam's soul back. Dean wonders how they can pull it off, and Sam goes outside and calls to Castiel. When the angel doesn't respond, Sam makes up a story of an artifact and Castiel arrives. He explains that he's busy dealing with the war in Heaven, but Sam insists that Castiel owes him, and demands that they help. When Castiel refuses, Sam threatens to spend the rest of his life finding a way to kill Castiel and then using it. The angel relents, but says that Sam needs help. Sam ignores his intent and says that right now, he needs Castiel to help them.
Sam and Castiel go back into the motel room to talk to Dean, and Sam claims that Castiel is helping them as a friend. When Castiel can't locate Crowley because of his magical wards, they go to the Campbell compound to search for information on Crowley's location. Samuel interrupts them and asks what they're doing there. Dean asks Castiel for a minute alone and then asks Samuel for help finding Crowley. When Samuel refuses, Dean asks why he'd choose Crowley over his own grandchildren, Samuel finally tells the brothers that Crowley has promised to bring Mary Winchester back in return for his assistance. Dean warns him that that's how the bad guys get them every time, by bringing back family members, but Samuel insists that he has no choice. When dean asks what will happen when Mary learns that Samuel chose Crowley over his grandchildren, Samuel tells them to get out.
Back at the motel, Castiel watches porn on the cable channel while Sam and Dean research for clues. Samuel shows up and offers to help them because it's what Mary would want. He gives them Crowley's location on a map, but refuses to go with them, insisting that it's suicide.
Later, Meg and her three demon minions arrive and Castiel is dismayed to learn that their working with abominations. Meg asks for Crowley's location, but Sam points out that they'll kill the Winchesters once she has the information. He asks for the demon-killing knife that she took from them, and then uses it to kill one of the demons, insisting it was more interested in killing the Winchesters than Crowley. He tells Meg that he did her a favor, and holds onto the knife. Meg smiles seductively at Castiel and then leaves.
Once Sam is outside, Castiel tells Dean that Sam's soul has been tortured by Lucifer and Michael for the last year, and if it's returned then it could destroy Sam emotionally and psychically. Dean says that right now, the priority is to get the soul back, and they can deal with the repercussions later. Castiel reluctantly agrees, but warns that the odds are that Sam will be mentally destroyed. They're unaware that Sam is at the door, and has heard the entire conversation.
Castiel and the Winchesters meet Meg and her remaining two demons at Crowley's location, an abandoned prison. Castiel teleports inside and lets them in via a side door, and they find a number of monsters held prisoner. They're forced to ignore the prisoners, but hellhounds come after them. The group makes a run for it, but the hellhounds bring down the two demons while everyone else barricades a door and seals it with salt. The hellhounds pound at the door and the salt line starts to break. Meg tries to leave her host body and get away, but discovers that Crowley has cast a spell on the prison to keep her trapped. Sam notes that Meg is the only one who can see the hellhounds and gives her the demon-killing knife. He asks her to buy them time to find and kill Crowley, and she agrees. Before she goes, she kisses Castiel, who kisses her back hard. Surprised, Meg breaks off after a minute, then tells them to run and goes to confront the hellhounds.
As Dean, Sam, and Castiel explore the prison, Castiel is suddenly banished back to Heaven. The brothers realize that Samuel is responsible: he's sold them out to Crowley. Crowley's minions capture them and Crowley himself arrives to tell them that they've outlived their usefulness and he's having them killed. His minions lock up the brothers in separate cells.
Meg finishes off the last of the invisible hellhounds, but Christian, still possessed by a demon, knocks her down and takes the knife from her.
Samuel comes to Dean's cell and tries to explain, telling her that he's chosen Mary and that Dean is the one who sold out his mother, Samuel's daughter. When Dean says that they're his grandchildren, Samuel says that he doesn't know what Sam is, and Dean is a stranger. When he asks who Dean is, Dean says that he's the one who will hunt him down and kill him for his betrayal. Samuel steps aside and watches as the demons come to take Dean away.
Christian straps down Meg so she can't escape and prepares to torture her with the demon-killing knife.
When Sam is unable to find a way to escape, he bites into his own wrist.
The demons throw Dean into a room filled with half-eaten corpses, and then lock two ghouls in with him. They go back to get Sam, who is crouched on the other end of the room. When they come to get him, the hit an invisible barrier, and look up to discover that Sam has drawn a Devil's Trap on the ceiling in his own blood. He runs out, finds Dean, and brutally kills the two ghouls.
Meg continues to defy Christian, saying that all he's doing is torturing her host body. She screams briefly in pain and then laughs. When Christian asks her what's so funny, Dean comes behind him, grabs the knife, and kills him with it.
Crowley prepares to torture a djinn when the alarm goes off. He goes to investigate and finds Dean waiting for him. Sam knocks him down from behind, directly beneath another Devil's Trap on the ceiling. Meg emerges and starts torturing him telekinetically, and Crowley finally admits that he can't return Sam's soul. The best he could do was get Sam's body out, and Lucifer and Michael will never let Sam's soul go. Crowley tells Sam that he doesn't need his soul, and that it would drive Sam insane if it was returned. Meg admits that he's telling the truth, and Sam tells her to kill off Crowley since he's now useless.
Meg takes the demon-killing knife and goes into the Devil's Trap to kill Crowley. He disarms her and throws the knife into the ceiling, breaking the Trap. He telekinetically pins Sam and Dean to the wall, and prepares to kill Meg with the knife. However, Castiel arrives holding a bag. Crowley taunts him, noting that Castiel is losing against Raphael. When Crowley asks what he has, the angel reveals that he's found Crowley's bones. He demands to know if Crowley was telling the truth about Sam's soul. When Crowley insists that he can't return it, Castiel burns the bones, destroying Crowley.
In the aftermath, Meg quickly leaves before they can kill her. Dean thanks Castiel, who warns that he's losing just as Crowley said, and he'd rather be spending his time on Earth. Dean says that as friends, they'll be there for him, but Castiel says that there's nothing they can do. Sam tells the angel that he'll have to deal with the imprisoned monsters, and Castiel agrees. Once he teleports away, Sam tells Dean that he's had enough: there's no point in fighting for a soul that will render him insane if he recovers it. Dean says that he needs the soul, but Sam disagrees and walks away despite his brother's pleas to stay.