Dean wakes up from memories of Hell… and finds himself in a coffin. He breaks through the lid and digs himself up, to find himself in a small clearing in the woods. Every tree in sight has been blasted backward from Dean's gravesite by the force of a vast explosion. He starts walking down the road to a nearby gas station, which is closed. He breaks through the door and finds a newspaper that says it's been four months since he "died." He checks himself in the mirror but sees no sign of injury from the wounds the hellhounds inflicted. However, there are claw marks on his shoulder. He takes some food and supplies but suddenly a high-pitched shrieking noise starts up. The TV comes on by itself and he tries to seal the building with salt, but a wind comes up and shatters all the windows.
Dean tries to call Sam but the number has been disconnected. When he calls Bobby and tries to explain that he's alive, Bobby angrily hangs up. Dean steals a car and goes to see Bobby, who draws a knife on him. Dean finally manages to convince Bobby he's real, cutting himself with a silver knife. Bobby explains that he and Sam both took Dean's death hard and Sam has gone off on his own to hunt demons. Before he left, Sam stated that he didn't want to burn and salt Dean's body since he thought they'd need it intact. They figure that Sam made some kind of deal or performed a ritual to bring him back.
They track Sam down through his cell phone account and go to his hotel in Pontiac, IL, near Dean's burial and resurrection. They find Sam with a woman, Kristy. He immediately attacks Dean and his brother finally convinces him he's the real deal. They get Kristy out and Dean demands to know what Sam did to bring him back to life. Sam denies having done anything and explains that he's been hunting down Lilith and is on the trail of two demons who came to Pontiac. They realize they need to get answers and Bobby suggests they contact a psychic friend of his, Pamela Barnes. While he leaves to make the call, Sam gives Dean his necklace back. Dean looks in the mirror and has vague memories of suffering in Hell.
Bobby sets up a meeting with Pamela and they hit the route. As their traveling, Sam explains what happened during his battle with Lilith and how he was immune to her powers. He claims that Ruby died and went back to Hell, and he hasn't been using his ESP abilities in honor of Dean's last wish. They meet with Pamela, who flirts with Sam and Dean, and they begin a séance. Pamela ends up contact an unidentified entity, Castiel, who tells her to turn back. She refuses and tries to press forward, and her eyes begin to flow. She falls to the ground, her eyes burned out.
The brothers go to a diner for lunch and get word from Bobby that Pamela is in stable condition. Dean wants to track down Castiel but the diner staff come over and the waitress sits down. Her eyes go black and she asks how Dean escaped from Hell. Dean admits he doesn't know but when they threaten him, he figures they're bluffing. He slaps the demon waitress repeatedly to provoke her but she doesn't kill him. He figures they're scared of whatever has the power to pull him out of Hell. Sam says they should kill the demons but Dean prefers to focus on whatever's responsible for his resurrection.
Back at the hotel, Sam sneaks out after Dean dozes off. Dean wakes up when the TV switches on and the high-pitched noise starts up again. He falls to his knees in pain then just manages to get out of the way as the ceiling mirror shatters and falls on the floor. Bobby responds to the commotion and the two decide to set a trap for Castiel. They call Sam, who claims he went out to get a burger. Dean doesn't tell him what they have planned, figuring that Sam would just try to stop them.
Sam is actually back at the diner. He goes in and discovers that the demon cook is dead, his eyes burned out. The waitress attacks him and Sam manages to hold her off. Her eyes are burned out as well and she says that her demons are dead and the end is coming. When she tries to attack Sam, he raises his hand and uses his ability to cast the demon out of the human host and then send it back to Hell. Kristy comes in and clearly knows what's coming on. Sam addresses her as Ruby and she figures they're up against some cosmic force more powerful than anything either one of them has experienced.
Dean and Bobby find an abandoned farm and paint the walls with runes and sigils while assembling a variety of weapons and mystic objects. Bobby starts the ritual to summon Castiel.
At the diner, Sam insists that he doesn't plan to tell Dean what's going on and they need to continue what they're doing.
The farm starts to shake and the lights explode. Castiel, an average-looking man in a trench coat enters the barn, ignoring the wards and the bullets Bobby and Dean fire at him. The man says he's the one who brought Dean back from Hell. Dean stabs him with Ruby's demon-killing knife but Castiel barely seems to notice it. He casually renders Bobby unconscious and then says he needs to talk to Dean alone. He says he's an angel of the lord and reveals his wings. Castiel explains that the sound of his true voice can prove troubling to mere mortals but he had hoped Dean could withstand it. A glimpse of his true body is enough o burn out the eyes of those who look upon him, which is why he warned Pamela to look away. To shield mortals from his true glory, he has occupied the body of a devout man who volunteered his services. When Dean asks why he was brought back to life, Castiel says that God commanded it and they now have work to do.