At St. Anne's Cathedral in Emory Park, IA, a man and a woman approach two priests as they go in for the night. The woman says that they're looking for a friend and figures that the priests know where he is.
The next day, Castiel is living at St. Anne's shelter in town. He informs a friend and co-worker that he's going to be moving on that night, and talks about his urination problems. Castiel then goes to work at the church picking up litter but notices blood on the ground and on the fence leading to the church cemetery. When he goes in, he finds the two priests mounted on poles, their eyes burned out.
Dean wakes up in the morning and wonders where Sam is. Sam comes in with food and says that he went out for a morning run because he's feeling so good. Ezekiel takes over Sam's body and tells Dean that Sam is healing but it's slow work. He then tells Dean that some of the angels have formed a faction to track down Castiel, and are recruiting humans as host bodies. Dean wonders if they're working for Naomi but Ezekiel admits that he hasn't heard her name mention. When Ezekiel continues to occupy Sam's body, Dean finally tells him to relinquish control. Sam starts talking again and Dean tells his brother that angels are organizing, even though he can't explain how he knows.
Reverend Buddy Boyle is sending podcasts out across the Internet, talking about angels and how people should embrace them. After he finishes his broadcast, he meets with his partner, the angel Bartholomew. Bartholomew claims that God is pleased with Buddy and has a special reward for him. Buddy brings in a female assistant who proclaims that she's ready to become host to an angel. Bartholomew summons an angel forth to fill her body, but she explodes from the angelic grace. As the angel wipes off the blood, he tells a shocked Buddy that not everyone can accept Heaven's grace and that some sacrifices are necessary, and Buddy quickly accepts the angel's claims.
At the Letters HQ, Sam and Dean try to work out where Castiel could be based on how far he could travel and where he called them from. They see an Internet news headline on the dead women and figure that the angels are responsible, and also turn up the story on the dead priests in Iowa. Dean figures that Castiel is near the Emory Park church and the angels are looking for him there, and the brothers head out to investigate.
Castiel shacks up at a homeless camp beneath a bridge and talks to their leader about how he is still trying to work out how to sleep and to accept that he'll die eventually. The former angel goes to an abandoned bus to try and sleep, but hears someone outside. When he goes to investigate, an angel wearing a pharmacist's body attacks him. The angel is shocked to discover that Castiel can bleed, and Castiel manages to kill him with his angel blade.
Sam and Dean visit the church and talk to Castiel's friend from the shelter. He tells them that Castiel was there until the priests were murdered and then left the next day, but he doesn't know where Castiel was going. Sam checks the Internet and turns up the murder of the pharmacist in Ohio, and the brothers figure that Castiel is involved.
Castiel is out on the street and goes to a tattoo parlor to use the last of his money to have them put an Enochian ward on his chest.
The angels from the church report to Bartholomew that the other angels are finding bodies thanks to Buddy's promotional efforts. Bartholomew notes that they let Castiel escape them, and they're forced to tell him that their Dayton operative was killed. Furious, their superior tells them to find Castiel, but they report that he's warded himself from detection.
Castiel finally takes refuge in a church and listens as a woman prays for her husband to recover from his illness. As she goes, Castiel talks to her about her husband and she tells him that people pray because sometimes they need someone stronger to turn to for help. The fallen angel suggests that God is gone and isn't listening to her, but the woman says that it isn't possible. Castiel says that he knows, but the woman says that it's possible because that's her faith, and his disbelief doesn't cancel out what she believes. She tells Castiel to try believing like she does, promising him that someone is listening.
Bartholomew summons a Reaper, Maurice, and explains that he needs a freelance Reaper to track down Castiel. Maurice agrees but says that he needs a starting point, and Bartholomew tells him to start with the Winchesters.
Posing as FBI agents, Dean and Sam go to Ohio and talk to the detective in charge of the pharmacist's murder. He describes a typical angel death and notes that the man had a clean history and was a religious man. The brothers checking the pharmacist's belongings and find an iPod with a download of one of Buddy's sermons. They figure that the angels are using Buddy to "recruit" humans to be their host bodies, and confirm that Buddy has adherents across the world. The brothers leave to check the crime scene, unaware that Maurice is following them.
Castiel is in an alleyway going through a dumpster for food when a busboy throws out some food. Once he leaves, Castiel goes over to take some of it. A woman, April Kelly, comes out of a door and Castiel eyes her nervously. She assures him that she's not a cop and offers him a peanut butter and jelly sandwich. Castiel doesn't want to take it but April says that she's offering it and gives it to him, and then goes back inside.
Sam and Dean go to the bridge and talk to the man in charge. He recognizes their description of Castiel and tells them that he left. Maurice watches them as the homeless man tells the Winchesters that Castiel left on a truck heading for Detroit.
That night, Castiel is out in the rain trying to stay warm in the alleyway. April comes out again and sees him and invites Castiel to come home with her. When they get to her apartment, April admits that she doesn't usually bring strange men home. As Castiel removes his coat, April notices that he has blood on his shirt.
As Sam and Dean pick up some pie, they go into an alleyway and Maurice follows them. They easily get the drop on him and demand to know why he's been following them.
As April bandages Castiel's wound, he explains that he stabbed his attacker and the man exploded. April wonders how it happened and Castiel tells her that he suffered from vanity and thought that he could fix everything. Now he's on the run because of his lack of humility. Noting that his back is all tensed up, April starts to massage his shoulder and Castiel admits that things like hunger and cold--and loneliness--are new to him. She tells him that she's not alone and kisses him, and Castiel hesitantly kisses her back.
Dean and Sam take Maurice to an abandoned building and torture him with an angel blade. He finally admits that Naomi is dead and that Bartholomew is now the one in charge. The Reaper dares them to kill him, warning that someone else will come after them to take his place. After they're satisfied Maurice has told them everything he knows, Dean kills him.
After he has sex with April, Castiel asks her if he did okay. She assures him that he did fine but notes that he's carrying a heavy load of guilt. Castiel admits that he's no angel and has done foolish things, and April wonders what he'll do next. Castiel suggests that they start with another round of sex.
The next morning, April makes breakfast and Castiel realizes that she washed his clothing. He goes through them looking for his angel blade, and April takes it out and mockingly asks him if it's what he's looking for.
When they're unable to find Castiel, Dean finally pulls over and addresses Sam, telling Ezekiel that he's had enough of pointless searching. Ezekiel takes over Sam and Dean asks him to help find the Reaper that has taken Maurice's place. Ezekiel reluctantly agrees to use his abilities to find their target.
April, a Reaper, explains that she didn't kill Castiel right away because she wasn't sure how dangerous he was. She also wanted to find out how much he knew, and admits that she appreciated the "fringe benefits" because he was attractive. April then gets down to business and starts cutting Castiel with her own angel blade, demanding to know how the angels can undo Metatron's spell so the angels can return to Heaven. Castiel insists that that he doesn't know and that he was tricked by the Scribe of God, but April doesn't believe him. He finally admits that Metatron took his grace to power the spell, and warns that if April kills him that she may be destroying the only chance to undo the spell.
Dean and the possessed Sam burst in and April stabs Castiel in the chest to keep him from interfering. She then slams the intruders away with a gesture and goes to kill Sam. Dean grabs the angel blade out of Castiel's chest and kills April with it. Realizing that Castiel is dead, Dean begs Ezekiel to resurrect him. The angel does so and the shock knocks Sam's body down. Castiel wakes up and asks how Dean brought him back, and Sam wakes up and wonders the same. Dean hastily lies and claims that he made a deal with April to bring Castiel back, and then killed her anyway.
The brothers take Castiel back to the Men of Letters bunker and Sam wonders how Dean found Castiel. Dean gives him a story about how he found an address on Maurice, even though Sam doesn't remember him finding it. Castiel enjoys the bunker's amenities and tells the Winchesters that he's learned that he can't let give in to anger or despair or hedonism. They wonder about the hedonism and Castiel says that April provided him with an... education. As the Winchesters eye him with new respect, Castiel says that he can appreciate how well they've lived their lives and figures that they'll be good teachers.
As Castiel goes to eat some more burritos, Ezekiel takes over Sam's body and tells Dean that the angels will eventually track Castiel down to the bunker, and it can't withstand their attacks. Dean refuses to toss Castiel out, but Ezekiel warns that Bartholomew and his angels will soon arrive. The angel then tells Dean that if Castiel stays, then he has to abandon Sam's body rather than endanger himself. Dean takes that in and then goes to Castiel and tells him that he has to leave.