Bobby and the Winchesters stare at Castiel for a moment, and the Bobby kneels and suggests that the brothers do as well. As they do, Castiel says that there's no point if they do it out of fear rather than respect. He tells them to get up and Dean tries to appeal to him, but Castiel says that the Castiel they knew is gone and that there is no need for him to kill them given they're powerless against him. He calls them pets and tells them that if they rise up against him, he'll kill them. Sam starts to feel the influence of his restored memories, and Castiel says that he won't restore Sam as promised since the brothers turned against him. He tells them that for their sake, he hopes it's the last they see of him, and then disappears. Sam feels his memories of Hell come back and collapses.
Castiel returns to Heaven and tells the angels that they need a firm hand and free will isn't the answer. He tells them that they need a father, and he is their father now... and leaves a field of dead rebel angels behind.
Later, Dean and Bobby work on the wrecked Impala at Bobby's junkyard. Bobby wonders what they can do against Castiel and admits that he's like nothing they've ever encountered. Dean snaps at him briefly but then admits that he's right and vows to do what he can, starting with fixing the Impala. He goes inside and Sam is there and says that he's feeling okay but doesn't remember what happened with Castiel. As Dean goes outside, Sam briefly hears clinking chains from the room behind him.
At the Serenity Church, a preacher rails against homosexuals and says that someone has to speak for God. Castiel appears and condemns the reverend as a hypocrite, and says that he can't speak for him. He introduces himself as God and crushes down a man who tries to get up. Castiel then causes the reverend to literally choke on his own words, and then tells the congregation that he is their God. As Castiel turns to go, he hears a voice whispering his name and wavers momentarily, but then gets up and causes his image to appear on the stained glass windows... unaware that his hand has caused a pew to smolder beneath his touch.
As Sam gets some tools from the basement, he has more visions of Hell and sees chains and burning flesh. Bobby comes down and finds Sam cowering in a corner and wielding a tool. Sam snaps out of his vision and goes with him to where they are watching the TV. The newscasters are announcing that 200 religious leaders have died across the country. As Dean continues to work, white-supremacy groups and motivational speakers are struck down as well and he figures that Castiel is off the deep end. Sam wonders what they can do but Dean says that there's nothing they can do but get out of the way of God and his brother agrees.
In a Tennessee trailer court, Crowley is watching the news when Castiel arrives, easily bypassing his wards. Castiel explains that he has plans for him and explains that he'll control the flow of souls and Crowley, as the King of Hell, will take what he gives him. He admits that he needs Hell as a threat for his enemies, and that they need to keep Michael and Lucifer in their cage. Crowley realizes that it's not a negotiation and immediately accepts. Castiel looks at his hand and sees burn marks, and then teleports away.
As Sam works alone in the library, a chain suddenly breaks through the ceiling, wraps around his neck, and lifts him up into the air as laughter echoes around him. As he strangles, Sam snaps out of his dream and wakes up. He calls to Dean and Bobby but gets no answer. Outside, Bobby and Dean finish the work on the Impala. Bobby wonders how Sam can be okay but Dean says that he's willing to accept it without asking questions. As Sam comes out, he hears Dean admit that he's not so sure that Sam is okay, simply because they never catch a break. Sam enters the garage and tells them Castiel's body count is increasing. They wonder if there is something in the Heavenly arsenal that might hurt Castiel but Dean says that there's nothing that can hurt God... but he thinks there might be someone.
The brothers summon Crowley, who explains that Castiel is his boss and everyone else's. He figures they want to conspire with him and Dean asks for a spell to bind Death. Crowley warns that Castiel could smite them in an instance but has no choice but to agree.
Castiel goes to see a blind beggar and says that he's a righteous man, and cures his blindness with a touch. He looks up at Castiel and sees burn marks and asks what's wrong. Castiel finds a mirror and hears the words "mistake" and "let us out" echoing in his head. He looks at his chest and sees hands trying to break out through his skin.
Bobby comes down in the morning and discovers that Crowley has slipped them an envelope with Death-binding spell. They put together what components they can but Bobby says that they need a fulgurite, a piece of crystal fused in the shape of the lightning that hit it. He's found Dr. Weiss, a bidder who won it and lives nine hours away. They arrive that night and beak in, knocking out the security guard, and Dean breaks in. The owner, Dr. Weiss, captures him at gunpoint but Dean quickly subdues the man and his wife and ties them up. Sam and Bobby arrive and they find the fulgurite and prepare the ritual. Bobby speaks the words and the entire house shakes.
Death appears, bound, and Dean offers him a fried pickle chip. Unimpressed, Death assumes that it's about Sam and says that he can only make one wall per customer. Dean is surprised, unaware of his brother's arrangement with Death. They explain that they need him to kill Castiel and Death wonders why he should. Before Death can answer, Castiel appears and says that he has no choice but to kill them. Dean points out that Castiel can't kill them as long as they control Death, and Death notes that Castiel's host body is breaking under the stress. He warns that there are older things than the souls in Purgatory and that Castiel can't handle them. God created the Leviathans but realized that they were too dangerous and locked them away in Purgatory. Castiel is now the only thing holding them back, but Castiel insists that he did a service taking God's place and cleaning up all the messes. He asks Death what he really is and says that he should take him out. Death says that he knows God and Castiel is no God.
Dean calls upon Death to kill Castiel and Death agrees. Castiel frees him first and Death sits down and says that he knew he'd be reaping someone very soon. Before he can do anything else, Castiel disappears.
At Senator Michelle Walker's election headquarters, Castiel arrives, insisting that he's not petty, and mutters to an aide that he's going to eliminate the senator because she's abusing people in his name. He tells everyone there that he's a better God than his father.
Death finishes his soda and pickle chips and says that Dean should have stopped Castiel long ago after he warned the Winchesters. He suggests that he should save his efforts for a better planet and prepares to leave, but Sam asks him for something. Death admits that he finds Castiel arrogant and tells the Winchesters that Castiel has to return the Leviathans to Purgatory. He tells them to lure Castiel back to the lab and use the eclipse that he'll create for them at exactly 3:59 a.m. Sunday morning to send the Leviathans back. After warning them that he'll kill them all if they try to bind him again, Death departs.
Castiel wakes up and finds himself covered in blood and surrounded by all of the senator's dead aides. The whispering of the Leviathans echoes in his head as Castiel stares around in disbelief.
The next morning, Sam comes to see Dean, who is drinking. Dean says that there's no way they can get Castiel to the lab and that he's giving up. Sam insists that they can do it but Dean points out that he lied about his hallucinations. In response, Sam says that there's nothing Dean could do so he kept it to himself, but Dean says he's giving up and will stick to drinking. However, he discovers an article about Castiel's slaughter at the senator's campaign office. There's security footage that reveals that Castiel smirked as he slaughtered them, and Dean figures there's no way to reach him.
Sam goes out into the junkyard alone and preys to Castiel. He insists that Castiel is still one of them deep down and asks him to let them help. He goes back inside and has a drunken Dean turn off his porn, and then takes a drink himself. Castiel appears, covered in blood, and says that he needs their help.
The brothers and Bobby get Castiel to Crowley's lab and prepare the ritual. As they work, Castiel apologizes to Dean and says that if he were stronger, he'd fix Sam. However, he admits that apologizing isn't making him feel any better. Meanwhile, Sam finds the blood they need and comes face-to-face with Lucifer. Lucifer admits that he's still in Hell and Sam figures that it's another leaking memory from the cage. As he tries to go, Lucifer says that his theory is wrong and that he's making Sam think that he's free. Lucifer claims that Sam is still in the cage with him and the entire thing is another form of torture.
The eclipse approaches and Dean goes to find Sam, but only finds the discarded blood. He takes it back and prepares the ritual, putting Castiel in front of the doorway glyph. Bobby reads the ritual while Dean holds Castiel up. Castiel says that he's sorry as the doorway opens and the souls and Leviathans flow out of his body and back to Purgatory. Once the ritual is done, Castiel collapses, apparently dead. As Dean complains that Castiel should have listened to him, Castiel's burns heal and he wakes up. He thanks them both for their help and admits that he's ashamed for overreaching. Castiel promises to find a way to redeem himself with them and then tells them to run. He warns that the Leviathans have held onto him and are still inside as his eyes turn black. Bobby and Dean start to run but the possessed Castiel says that it's too late and that they run the show now. He throws Dean and Bobby into the wall as black veins spread across his face and he says that now he's going to have fun.