Chapter 28.
When they got to the Impala. Sam gestured to the passenger door. "Just this once, you get to ride shotgun."
Cas opened the door. "I'm still not sure this is a good idea."
"I'm not sure either." said Sam, "But I'm not coming up with any other options and neither are you, so let's trust Sarah."
Sarah got into the back seat and made herself comfortable. "Get in, both of you."
They obeyed. Sam started the engine.
"Don't play any of his music." said Cas.
Sam could understand that. He needed no reminders of Dean either. "Fine. No music." he said, "Any preference on direction?"
"Unless you know where Dean is, all roads are equally pointless." said Cas.
"Just a no would have worked." said Sam, as they headed out.
"Are you okay to drive?" said Sarah, "Because Castiel and I can both drive if not."
"I've driven on a lot less sleep." said Sam.
"I have every confidence in you." she said, "You two go ahead and talk."
They drove for some time in silence, then Sam said, "Before you shoot this idea down, Cas, I do know all the arguments against it, including that it could open a mental link between us that you may not want."
"That sounds like a bad idea, especially if you also don't want it." said Cas.
"I'm not pulling a Dean here." said Sam, "I'll be honest. I envied you and Dean your link and I'd like to be able to communicate with you like that, but I do have doubts. Sarah thinks we should be open about our pain, but the thought of giving you more to deal with ... "
"I can take it. My question is, can you?"
"The way I see it," said Sarah, "Is that both of you are already wounded by each other's pain and both of you have thoughts tearing you apart that you cannot discuss with anyone else."
"Plus, you already shared my Hell." said Sam, "It's about time I took a share of yours. Most importantly, though, I want to show you my thoughts, so you know there is nothing in there that blames you or hates you or wants you to leave. In fact, I'm terrified that you'll leave and we'll never be able to get you back."
"Like Dean?" said Cas.
"I hope not. Look, Cas, you and Dean were working so well with the connection. You had it under control. You could both choose to use it or keep it closed. Now, I think you and I could start it out by choice and build into it the kind of control you and Dean were eventually able to use."
"Dean and I were a special case." said Cas.
"Right. More profound bond. I know. But I can't give you Dean. I wish I could."
Cas was looking at him, saying nothing.
"What?" said Sam.
"The more profound bond thing. I really hurt you when I said that, didn't I?" said Cas.
"What? No! No, I get it."
"Sam, I had no understanding of human feelings and little concern for them. I spoke the truth as I understood it, but I understood almost nothing."
"It was true."
"In some ways, at the time, perhaps. It's not true now. You and I have shared things Dean can never understand. My hesitation is not because I don't desire mental communion with you, it's that I cannot offer you clarity or sanity or nice, comfortable emotions." He touched his head. "This is a Hellscape of confusion and pain and fury."
"Mine too."
"Yours is controlled, limited. Mine is boundless and untempered by any kind of wilful control. Sam, I should be in complete control of my mind and I am not. I fear to look within. I fear insanity."
"Right there with you." said Sam, "So let's do this together."
"You're not understanding me. I know you. For years, I've seen you tread the fine line between functional instability and screaming insanity and I'll admit, I have marvelled at your ability to do so. You kept going when anyone else would be incapacitated."
"You think this will push me over the edge?" said Sam.
"Don't you? You know me too, Sam. You know what I can bear. Now, I am telling you that this is beyond bearing. This is what will destroy me and I can live with that. I can't live with it destroying you and Jules and Jack and Sarah."
"It won't push me over the edge."
"You can't be sure of that." said Cas.
"I can, because I left the edge behind a long time ago. I've been freefalling for years. You fear insanity. I had to learn to live with it, even to embrace it. I am the one person this darkness you're in can't harm, because darkness is part of who I am."
"I'm not sure I agree with that." said Sarah.
"Until Dean was gone, I didn't know how much I was relying on him to keep me ... well, not sane, but close enough to it to be useful. He always said nothing bad would happen to me while he was around."
"The past decade has disproved that." said Cas.
"Maybe, but it still feels true. And now Dean is gone. I feel like I've been hit by a truck and then time has frozen in that moment and the pain and shock of the impact have become eternal. If you're broken, so am I, Cas and we both know, the only way through this is each other. Neither of us is going to find a way to live for ourselves."
"That is probably true." said Cas, "Of course, there may be no connection formed. Dean and I have theories, but we never really came to any firm conclusions. It might not cause a link to open."
"It might not." said Sam, "But I think it's more likely to open one if we consciously try to do so. At the same time, we can put in a kill switch."
"That sounds a little ominous." said Sarah.
"I just mean a way for either of us to shut it down at any time, temporarily or permanently. If we include it in the initial parameters, control should not be a problem and both of us get to have privacy any time we like."
"Why are you even considering this?" said Cas.
Sam sighed and said what Dean might say, "Because you're my brother, dumbass!"