Disclaimer is in part one

Castiel pushes back his own sleeve. "True penitence must always stay Heaven's wrath," he says as he slashes his own arm, scoring the same muscle he sliced in Dean's gilded cage. The previous cut is gone. He places his arm before Sam. "Drink this."

Sam, no longer limp, recoils. Castiel holds him fast. Sam starts to speak, but his words die as he looks into Castiel's face.

"Cas, stop this." Dean pounds the solid air. "Let me in." Castiel nods and Dean nearly falls forward as the invisible barrier drops. Dean stumbles to crouch down beside them. The fire moves closer, burning the fallen trees. Castiel looks only at Sam.

"Drink," Castiel says, expressionless.

"Oh, Dude," Dean says. "This is so sick." He looks into Sam's wide, frightened eyes. Human eyes. Afraid of doing it, afraid of what Dean will think. "Oh, go on, Sammy, what the hell. But I can't watch." Dean looks away. When he looks back, Sam is slumped against Castiel, eyes closed. Castiel rolls down his sleeve. The smoke is so thick, Dean starts to cough. Heat, as from an open oven, warms one side of his face.

Dean touches the crown of Sam's head. "What did you do to him?"

"He's done it himself. He's struggling now with conflicting powers."

Sam moans. "Yeah? The last time that happened, he started flinging himself all over the room. Is that going to happen again?"

"I don't know."

Around them the burning forest fades into quilted white and Dean's lungs are grateful. "A padded cell. How thoughtful." Dean's energy for sarcasm fades when he looked back at Castiel's stressed features. The angel sits against a soft cell wall, Sam lying restlessly against his legs. "Will this … cure him?"

"I don't know." There is no mistaking Castiel's exhaustion. "It isn't the blood. That's just the vehicle he's used to. Now he has some grace to power his choices. It might work."

Hope, an odd thing to feel at the end of the world, floods into Dean. "Thanks. Thanks, really. I know … you could have put me back in the hotbox any time, I know that. I'm sorry I was such a prick about it. God, I'm tired of saying I'm sorry. But, thanks." Dean eyes Castiel. He considers that Castiel could have been out there, with the other angels, fighting, doing whatever it is they do, but instead two sorry humans are his only companions. "Are you all right?"

"I am badly weakened, and something has eclipsed the light of the Presence."

"What does that mean? Is that something Lucifer does?"

"Perhaps. It could be my superiors, cutting me off."

"Your superiors. These are the guys who decided to bring on a war, because they figured they could win it. How could you hang with those pricks?"

"If Heaven is victorious in this battle, they can create a paradise on Earth. It is a noble goal, and may be my Father's will."

"Yeah, but what about the people who live here now?"

Castiel shifts against the cell wall as if Sam's weight or something else makes him uncomfortable. "Untold suffering. It has already begun. They are viewed as an acceptable sacrifice for the long-term good."

"You don't buy that, Cas. I remember when you used to like to watch kids playing on a playground." Dean realizes the futility of arguing with Cas – the futility of almost anything, now. "Speaking as one of the acceptable sacrifices here … not that what I think matters."

Castiel's voice is stronger, more intense, his gaze serious. "It matters to me. I want you to lead me again. I don't know what my Father's will is, but I have chosen my side. I remember the playgrounds. And I remember a time when all Heaven's forces served the good of Man. Your choices have always been for the good of Man. The good of a town, the good of the world, the good of your brother. My allegiance has been split and my motives corrupted. I will follow you."

"Whoa, wait a minute, here! You don't follow me. You're an angel! I'm just some human schmuck. No, don't start. You should have seen me in Hell. I tortured souls like crazy. I broke the first seal! I failed to stop Sam and Lucifer. Shit, I am nothing but a fuck-up."

"Dean, there is a truth that has escaped you. Souls go to Hell because it is divine judgment that they be punished. What you did, horrible as it was, was serving God."

"Oh, right. So now it's God's will that we have Hell on Earth? I enjoyed torturing, Cas. I enjoyed it."

"I did not say you are an entirely admirable man. I said I admire your choices. Until I can make my own reliably, I will follow yours. But, if it upsets you, I'll say no more about it."

"Good. Just, don't. Besides, you're talking like we have a future here. This is the apocalypse. Sam and I are going to be part of this untold suffering party."

"Probably. But you can also do what your father taught you. Protect the innocent."

"With a full-up Apocalypse Now going on, how am I going to do that?"

"If Sam chooses to join you, he may retain some of his abilities. No one else will be looking out for humanity." Dean looks at Sam, and the possibility of facing Armageddon without him settles in his belly like a stone. Until he rejects it. That won't happen, unless Sam doesn't live. Dean studies his brother's face, sees unhappiness there, but not violence and pain. Not like the last time. It doesn't sound so bad. With Sam at his side they can go down fighting the things they've always fought. If only they could have stopped this. Dean winces under the weight of guilt and failure, and then puts it aside. He's a pragmatist. This is the way things are. They both wanted to be the hero, and they both failed. Fuck it.

With some of his fighting spirit reviving, it bothers him to see Castiel looking so wiped. "What about you?"

"I will help, if I live. I will leave my vessel before I die, Dean, to spare him. Promise me you'll help him."

"I'm not going to kick the guy to the curb or anything, but Cas, are you really dying? Because of this blinded by the light thing or whatever it was?"

"I am not only a servant of God, I am a manifestation of Him. I am sustained by connection to His divine presence. It's like the air you breathe. Something has cut it off. I've never experienced this before."

"We've got to find this thing that's doing that and stop it."

Castiel, who never smiles, smiles slightly at Dean's bravado. "There is another way. You can help me."

"How?"

"You won't like it."

"Ha. This is me, laughing my ass off. I won't like it. What now?"