|A police officer, Gerald Hatch, returns to the station locker room and discovers that he's bleeding from a cut on his cheek. He tries to wipe it off but discovers that his skin is peeling off. Blood starts oozing out of his every pore. He collapses and explodes into a bundle of loose flesh as his partner, Ed Colfax, looks on in horror.
Dean dreams that he's sleeping in bed and wakes up in Lisa's arms. He then snaps awake, realizing he's in the Impala. While he drives off, Sam is at his apartment saying goodbye to a woman he spent the night with. He refuses to answer any of her questions, intriguing her further, and then pays her. She tells him to call her on her night off. Sam then calls Dean and says he has a case in Easter, PA, and tells Dean to meet him there.
Patrolman Toby Gray is watching for speeders when a car drives by him at 70 MPH, but he's too busy taking a nip of something he's adding to his soda. He's unaware that someone is watching him from the nearby woods. His phone rings and he tells the caller that someone is dead, and it has nothing to do with either one of them. Once he hangs up, boils suddenly spread across his skin. He tries to call in for help but dies in a matter of seconds.
As Dean meets up with Sam, he finishes talking to Ben on his cell phone. Sam asks how Lisa took the news, and says surprisingly well, and that it's better for everyone. They go into the police station morgue and Sam explains that Hatch died when he literally transformed into blood. He then shows Dean Gray's corpse, covered in boils. They figure something is going on and go to see Colfax, posing as FBI agents. Colfax tells them not to worry about Hatch's death and shuts the door on them. Sam kicks it in and they go inside. They discover that Colfax has scratched out the faces on all of his photos, and tells them again not to worry about it. He clutches at his head and pours himself a drink, and tells the Winchesters that he'll be the next to go and then it will be over and God will be satisfied. He mentions Christopher Birch and says he had no face. Colfax knocks over the bottle and stares at it for a long moment, and then tells them that they planted a gun on Birch. Blood leaks out from beneath his hat, and he scratches at it and then falls over, dead. Sam confirms that he's dead and then removes the hat. Colfax's head is covered in locusts that have bored out of his skull.
Back at the motel, the brothers realize all three ailments relate to the Biblical plagues of Egypt. Sam discovers that a kid named Christopher Birch was shot in the head, and Colfax, Hatch, and Gray planted a gun on him and filed the same report. Sam suggests that angels might be involved, striking at bad cops, and Dean suggests they call Castiel. Sam notes that he tried calling Cas when he was resurrected but had no success. Dean says his own unique prayer, and Castiel appears in the room. Sam wonders why Castiel came for Dean but not for him, and Castiel says he has a bond with Dean. He admits that they have no idea who brought Sam back or why, and it couldn't have been God because no one has seen Him. Castiel then explains that he came because of the plague deaths, and his angels aren't the ones responsible. However, one of their weapons is responsible: the Staff of Moses. Castiel admits that in the confusion following the Apocalypse, a number of their weapons have been stolen and asks them to help since his people skills are rusty. The brothers figure that Christopher Birch's father Darryl may know something.
Mr. Birch is reading an article about the officers' deaths, and tells his son Aaron to go play. He then starts cutting out the article. Castiel teleports in with Sam and Dean, and they tell him they know the truth. Darryl says that the officers are getting what they deserved. However, Birch has no idea what they're talking about. Aaron comes in, wielding a sawed-off piece of the Staff. Castiel renders Darryl unconscious and takes the staff from Aaron, and Dean gets the boy to explain that he killed the officers. Aaron tells them that an angel gave him part of the Staff after he prayed for vengeance on his brother's killers. Dean realizes that there's more, and Aaron admits that he gave up his soul in return for the staff. Castiel admits that it's never happened before -- an angel collecting souls -- but that it's possible.
Castiel renders Aaron unconscious, teleports them all to the motel, and explains that he can read the brand of the angel that bought the soul. Castiel admits that it will be painful and Dean objects, but Sam is okay as long as there's no permanent damage. Dean warns that Castiel is torturing a kid, but the angel says he can't afford the luxury of worrying about that. He inserts his hand into Aaron's body while Sam prevents Dean from interfering. Castiel finally gets the information he needs and explains that the angel responsible is Balthazar, a friend.
An angel suddenly appears in the room, thanks Castiel for getting the name, and attacks him. They struggle and Castiel shoves the angel out the window, where they both fall several stories onto Sam's car. The other angel disappears while Castiel pulls himself from the wreckage and teleports himself back upstairs. He explains that the angel works for the archangel Raphael. The brothers insist on getting an explanation, and Castiel admits that Raphael wants to rule Heaven, and Castiel and others are opposing himself. If Raphael wins, he will restart the Apocalypse. Castiel prepares a ritual and admits that he was ashamed to tell them what was happening because he expected more from his brothers. He then takes some of Dean's blood to complete the ritual and locates Balthazar. As the police approach, Castiel figures that they'll take the boy home.
Castiel teleports them to a manor and goes in, wielding his knife. Balthazar is relaxing and listening to music, and shows Castiel Raphael's soldier, dead with a frog in his throat. Balthazar explains that he faked his death and then stole the Staff of Moses along with many other weapons. Castiel insists that he's no thief, but Balthazar admits that he is. He assures Castiel that he'll help, but refuses to give the weapons back. Balthazar insists that he's following in Castiel's path of rebellion, and that he wants to live a life of complete and utter freedom. Now he plans to try everything, and laughs at Castiel for believing he can ever stop the fighting. Castiel tells him that he's insane, and warns him that Raphael will be coming. Balthazar is unimpressed, but thunder echoes outside. Balthazar teleports away as Raphael and his soldiers arrive outside.
As Raphael's soldiers advance on the house, Sam confronts one of them. However, he's just the distraction as Dean uses his blood in a sigil to banish it.
Inside the house, another soldier attacks Castiel, who reluctantly throws his knife into its chest. Raphael appears behind him and throws him into the next room, and assures him that the soldiers have sworn themselves to his service. He beats Castiel mercilessly and prepares to kill him, but Balthazar returns and uses another of the weapons to turn Raphael's host body into salt. Balthazar prepares to leave, but Dean traps him in a circle of flaming holy oil. They threaten to destroy him unless he releases Aaron's soul. Castiel backs them and Balthazar releases the soul. When Dean asks why, the angel explains that souls are the only thing of value. Dean refuses to release him, but Castiel extinguishes the circle and says that his debt is cleared. Both angels teleport away.
Later, Dean and Sam prepare to leave and Sam puts his stuff into the Impala. Dean asks his brother if he's okay, and notes that he didn't interfere when Castiel tortured Aaron. Sam doesn't see the problem, and explains that he's been hunting nonstop for the last year. Dean thinks that there's more going on, and that Hell changes a person, but Sam says that has overcome his problems and he's different. As Sam gets in the car, Dean looks at him skeptically.