With Sam dying in a hospital, Castiel MIA, and Dean helpless to save Sam or find Cas. After the Angels fall to Earth last season, Sam falls into a coma and the Doctors say it doesn't look good. Desperate, and angry, Dean heads to the hospitals chapel to pray to Cas, but when it doesn't work, Dean prays to any Angel who'll listen. Unfortunately for Dean, there are a lot of angry Angels out there who want to get their hands on Castiel. Dean heads to the Impala, where Crowley is supposedly in the trunk, to try and get Crowley to help, but is attacked by an Angel looking for Cas. Another Angel, saves Dean but is hurt in the process and passes out. Dean puts him in a ring of holy fire to keep him contained. The Angel, Ezekiel, agrees to help Dean, saying that not all Angels have forgotten their purpose nor the good Castiel did. Dean takes Ezekiel to see Sam.
Castiel, after nearly getting hit by a truck, get a ride with the man whom nearly killed him to a gas station and meets one of the fallen Angels, a woman who has no idea what to do. Cas helps her figure out what she wants to do: last time she was on Earth she created the Grand Canyon and wishes to visit it. Cas agrees to help her visit the Grand Canyon. He first gets in touch with Dean and learns of Ezekiel, whom he knows is a good and trustworthy Angel. He tells Dean about the Angel he's met and Dean tells him to ditch her and high tail it to the bunker for safety, and that the Angels are after him. Cas says that he wishes to help, he needs to help. Dean talks him into looking out for himself first for once and Cas tells the Angel that he can't help her got there, but she can do it by herself. As he's leaving her, she hits him in the head with a length of wood, knocking him out. She puts him in her car and starts driving.
Back at the hospital, Dean wards Sam's hospital room from Angels, which weakens the already weak Ezekiel, but the Angel says he's fine. More Angels show up and Dean decides he's to fight while Ezekiel tries to help Sam. Dean gets a little banged up, but sends the Angels away, only to get back into the room to find that Ezekiel says he's to weak to heal Sam the way he is. Dean wont take no for an answer though. Ezekiel offers a solution, that if he posses Sam, he can heal both Sam from the inside, and himself in the process, that he'll leave once Sam and him are healed. However, the catch is that Sam must willingly allow Ezekiel to posses him, which he can't do while unconscious.
Cas wakes up in the woman's car, head bleeding, and the woman holding an Angel blade in her lap as she drives. She talks about them joining together, because Metatron took Castiel's Grace, Castiel is now human and she could posses him and they could work together; however, Castiel wants nothing to do with it. Seeing that he wasn't going to get away from the Angel without a fight, Castiel notices she's not wearing her seatbelt. He puts his on and grabs the steering wheel, careening the car into road dividers that are piled up on the side of the road. Cas comes to to find that the Angel was thrown though the windshield and he goes to her: her body is severely wounded, both legs broken violently, glass embedded in her face, arms, legs, and abdomen. She threatens to go on Angel Radio and tell every Angel where they are if he leaves and doesn't allow her to posses him. Castiel is forced to kill her before leaving.
Dean isn't sure what to do, knowing that Sam would not agree to being possessed by an Angel after everything that's happened to him. But there's no other way to save him, so Ezekiel comes up with a plan to trick Sam into saying yes, which is okayed by Dean.
During this whole thing, Sam is in his coma, facing the fact that he's dying. He wakes up in the Impala with Dean driving, who also tells Sam he's dying and that they're in Sam's head. Dean representing the side of Sam that wants to fight and try to survive. Dream Dean tells Sam that he'll think of something. Bobby shows up in the back seat, representing the part of Sam that doesn't want to fight and just die. Both sides of Sam argue their sides and Sam isn't sure what he wants to do, though he's inching towards dying. Dream Bobby transports himself and Sam to a forest, while they talk about what Sam wants to do. Dream Bobby explains that it's Sam's time, that everyone has a time and things like that. They come to a cabin in the forest and Dream Bobby tells Sam that everything he needs to pass on is inside. But then Dream Bobby is stabbed in the back by Dream Dean and disappears. Dream Dean tries to talk Sam into trying to survive, but Sam essentially tells him it's his time and Dream Dean disappears. Inside the cabin Death is waiting. The talk, Death saying that it's an honor to be delivering Sam Winchester from Earth. Sam tells Death that he'll only go on one condition: he stays dead forever, no one can bring him back, ever. Death agrees, but then Dean shows up, not a Dream Dean either. Dean makes a quip about not brining Death a snack, and Death gives them some time. Dean talks Sam into not wanting to die, but Sam is confused as to what Dean could do to save him. Dean asks if that's a 'yes,' and Sam says Before Sam knows what's happening, Dean puts his hand on Sam's head, a bright Angel white light shining from both of them, and Dean's face momentarily turns into Ezekiel before the screen whites out. The body Ezekiel was possessing before wakes up in the hospital, not knowing what happened. Outside the hospital Dean and Sam are walking, only Sam isn't Sam, he's Ezekiel. Dean worries about his brother, and Ezekiel tells Dean that he must not tell Sam about him, because Sam can cast him out at any moment, and if Sam casts him out before he's healed, Sam will Die.
Some of the scenes are a bit out of order, but this is basically what happened during the episode. XD