Disclaimers are in part one
Castiel shifts his weight again, and Sam rolls off his leg. Sam lies on his side, his eyes still shut, but a tension in his frame says it is not sleep that grips him. "You are human," Castiel says, his own gaze on Sam. "Every human is born with divine grace." He looks steadily at Dean. "If you can show it to me, I should grow stronger from it."
Dean frowns. "Show you what?"
"Love?" Somewhere in Dean is laughter that borders on the hysterical. Could he please wake up from this twisted nightmare? "You want me to love you?"
"Love Sam. Love yourself. Love God, love anyone. I -- need you to feel it. It's an essence within you that's seldom on the outside, but is rich with the divine when it is."
"I – that's just – that's crazy."
"I said you would not like it." Is Dean imagining it, or does Castiel sigh?
Of all the things Dean has had to do, to try, to adapt to, this suddenly seems the weirdest. How exactly do you love someone on demand? "How – I mean, Sam …"
"Unless there is someone you love more?"
"Well, he's not exactly easy to love. At this point it's kind of like getting warm and fuzzy with the antichrist. What do I do, say 'I love you Sam?'"
"It could be a start. Dean, I don't know how to tell you how to feel something." Castiel closes his eyes.
"Okay, Okay." Dean doesn't even know where he is. If Cas actually dies, can they even get out of this cell? "At least he's still out of it." Dean looks at his brother like he inspects a bag without any pie. "Sammy I love you." He tries a different tone of voice. "I love you." It feels like one of Bobby's chants in a long dead language. Something meaningless that works a spell. "I love you. Oh, this is stupid."
Sam has relaxed, the tension gone from his face. Dean tries not listening to himself, just talking. "I love all of your … of course I really hate it when you … okay, I love you, I do. I loved Dad. I loved Mom." Now his eyes start stinging. "I loved those grandparents and Yellow-Eyes killed them. Oh, Cas, this hurts."
"Concentrate on Sam, then." Castiel's eyes are still closed.
Dean closes his own eyes. "Sammy I love you. I love you, I love you."
"Do you believe in fairies, too?" Dean snaps his eyes open to see Sam looking up at him.
"Geez!" Dean would kick him if he weren't on his knees.
Sam levers himself up on an elbow. "Should I clap my hands?"
Dean gets to his feet. "It wasn't for you. It was for him." He speaks hastily, then regrets the words when he sees the faint amusement on Sam's face fade. Sam looks at Castiel apprehensively, then scoots away from him with the briefest glance at his new surroundings.
"Cas, this isn't going to work," Dean says. "I'm sorry."
"What's not working?" Sam asks.
"Nothing. Sam, I didn't mean that I didn't mean it." He'd pace but there's not much room in a padded cell. "It's just that Superman there has a kryptonite problem. Are you all right?"
"You keep asking me that. I feel like shit. I knew stopping Lilith was supposed to be your gig and I went ahead and let myself think – Dean, I am so sorry. I thought you had come back from Hell too messed up. I told myself you were weak or something. How am I ever going to be all right?"
Dean remembers Sam's hands on his throat, strangling. Wondering if this thing that was once his brother would really kill him. He needs that to be over. He needs Sam back. "I meant, you know, angel blood? You feel any different?"
"No – I don't know." Sam seems to not want to look at Castiel. "What's the matter with him?"
"He's –" Dean doesn't want to say it. "Sick. Sam, listen. I swear, I locked you up to save you. I didn't know what it would do to you. I wasn't trying to hurt you. But then we had to see it through."
"I know, I know. And if I'd stayed in there, none of this would have happened. But it nearly killed me, Dean. I hated you for that. I hated you. I can't believe I was so stupid. I wish you didn't say what you said, though. I was almost thinking I might have been wrong."
"Hey, I should never have said that. But I already apologized for all that shit; I'm not up to it again."
"That's not what was on my voice-mail." Sam sits up, hugging his knees, a posture Dean has seen him use his whole life. "I heard you saying all the same things. Calling me a monster and how Dad was right to throw me out."
"Geez, man, that is not what I said."
"I believe you. I wish I could have heard what you did say, though." Sam's simple sadness tells Dean encyclopedias worth of what those words meant to his brother.
"Well, that's all over with. Um, anyway, that's not what I said."
"Here," says a low voice. Sam and Dean both look at Castiel, startled. The angel still sits with his eyes closed, but he holds out his hand. In it is Sam's cell phone. Dean makes a grab for it, but Sam is closer and has it in his grasp.
"Hey, the service probably doesn't even work anymore," Dean says as Sam thumbs his voice-mail and holds the phone to his ear. "What with the world going to shit out there and all." He gives up his protest as the faint sound of his own voice and the expression on Sam's face makes it moot. He watches reluctantly as the real phone message reduces Sam to sobbing into his bent knees. "Aw, crap," he says, kneeling, putting a cautious hand on Sam's back. He braces as Sam pulls him into a desperate hug.
Castiel opens his eyes and climbs easily to his feet, regarding them gravely. Still holding Sam, Dean says, "What are you looking at? You're a peeping tom and some kind of a love vampire."
Castiel nods. "Whatever you say, Dean."
The lights flicker and a klaxon sounds. With a mechanical click a door opens. Sam remains oblivious, but Dean looks at Castiel, concerned. "This is a real place?"
"It is under siege, too," Castiel says. "We should go."
"C'mon, Sam, get up. We gotta go fight the bad things." Unaccountably, Dean feels really good about that. There are worse ways to end.