Impossible. Freaking impossible.
"No way in hell is that happening," Dean insisted. Kevin and Sam both gave him a stern look, while Cas only seemed grimly accepting. Dean persisted though. "No. I- We," he corrected quickly, "Just got you back, man. No way are we letting you pull some sacrificial bullshit."
Sam opened his mouth to reply, but Cas held up his hand to stop him. "I believe it would be best if I spoke to Dean about this alone," he said softly, inclining his head towards Kevin and Sam significantly.
The boys both nodded, and they left the room. They'd been in the library of the bunker, but now Castiel craved a slightly more… comfortable setting in which to have this painful discussion. Without awaiting Dean's permission, he transported them both back to Dean's room, the only place in the bunker Castiel felt completely at ease.
Instead of complaining about the unwanted mojoing, Dean just sat down on the edge of the bed. "Cas, man, you aren't doing this."
Castiel pulled the chair from the corner –his chair, the chair Dean had left out for him, in the hopes of his return– and sat facing his hunter with a sense of serious determination.
"Dean," he began, "You and Sam are too valuable to be lost. I am, in the grand scheme, unimportant. And it is not as if I will cease to exist. I will Fall, but I do not believe it will destroy me." Cas sat back, hoping Dean would see reason.
But his hunter leaned closer, green eyes drowning in some sort of knowledge, and took the angel's hands in his own.
"Cas. I can't- I can't let you give up everything you are, for us. If you lose your grace… You'll lose yourself. It's not like Sam or me dying. We'd still be us, in our heavens. But you don't know who you'll become if you Fall." Dean shifted uncomfortably, flashing back to the future Zachariah had shown him. He never wanted to see Cas's eyes go dead like they had been, never wanted his angel brought so low that only drugs could numb the pain. He couldn't let it happen.
"What I know," Cas argued, "is that I cannot see you die, nor can I watch you suffer if Sam were to make the sacrifice. It is best I risk myself; you will lose nothing." He said it like it was the most obvious thing in the world, and not the complete opposite of truth. Dean scowled, gripping the angel's hands tighter.
"I would lose you," Dean said, eyes blazing now, anger and pain bubbling under his skin.
"As I said." Cas's voice was hollow now, his eyes going dull, too similar to the future Cas Dean had seen. "Nothing."
That last word, the affirmation that Cas had already lost so much of himself, broke something in Dean, making him release the angel's hands and instead grab him by the shoulders, crashing their lips together fiercely.
"Everything," Dean huffed when he pulled back a moment later, settling onto the edge of the bed once more. His brain finally caught up with his instincts, and terror settled into his bones. He'd crossed a line, he knew it, and if Cas's stunned gave was anything to go by, it was one hell of a line he'd blown past. He opened his mouth, an apology already on the tip of his tongue, when he found himself suddenly knocked back onto the mattress, Cas's lips pressing against his once more.
For the first time since Purgatory, Dean felt… happy. No, that wasn't the right word. Ecstatic. There was an edge of desperation to it, the fear that Cas might still go through with the plan to close Hell off, but most of it was buried under the wash of Cas that was covering every plane of his body and mind. After a moment of just savoring the feeling of Cas's slightly chapped lips on his, Dean parted his lips, encouraging Cas to do the same.
Dean had figured if this ever happened, he'd be the one running the show, but the moment Cas opened his mouth, Dean knew he was in for a ride. Then again, if it was his angel leading, there wasn't a place in the world Dean wouldn't follow.
Castiel threaded his fingers through Dean's hair, marveling that he was allowed to have this, that Dean was willing to give this to him in spite of his mistakes and the pain he had caused his hunter. Dean pulled back, just a little, and Castiel let him go only so he could catch his breath.
After a moment of hushed silence, punctuated only by their heaving breaths, Dean spoke. "Just… just don't do anything unless you're sure, okay?" he asked, and if Castiel didn't know better, he'd swear Dean was begging. He realized belatedly that Dean's hands were gripping his hips like they were a lifeline, holding their bodies close together.
The angel looked down at Dean, studying his face carefully. He seemed almost frightened; there was a protective sort of light in those green eyes that Castiel usually only saw aimed at Sam. Castiel leaned down, pressing his lips gently to Dean's brow, wanting to smooth away the lines of worry furrowing there.
"I'm already certain, Dean. I will not lose Sam, and I cannot lose you," Castiel said lowly, his voice rough with more emotion than he was used to expressing to Dean. "You have both sacrificed so much."
Dean sat up suddenly, holding onto Cas to keep him in his lap. "And you haven't? Castiel, you've given up everything for us, for me. And now you want to give up the last of what you have?" Dean shook his head and tightened his arms around the angel. "I can't ask you do to that."
"You aren't asking. I'm giving," Castiel whispered, leaning down so his forehead rested against Dean's. They sat like that for a time, Cas with his legs wrapped around Dean's waist and Dean holding tightly to Cas's waist, afraid if he let up on his grip the angel would mojo out and go on with the plan without him.
Castiel leaned forward, pressing a tentative kiss to Dean's lips, and when Dean sighed appreciatively, he deepened the kiss, slipping his tongue into Dean's mouth to taste him. Dean shuddered beneath him, finally joining in fully, pressing up towards Castiel urgently.
Without really thinking, Dean pushed Cas's trench coat off, loving the thump it made as it hit the mattress. He was working on tugging the tie off when he heard the door bang open.
"So get thi- Jeez, guys! Sock on the door next time!" Sam exclaimed, holding a book in one hand and a horrified expression on his face. Not oh-my-God-my-brother-likes-dudes face (they'd had that talk ages ago) but very much an oh-my-God-my-brother-is-banging-an-angel face.
"My bad, Samantha, I forgot you don't knock," Dean teased easily, holding Cas in place when he went to move off Dean's lap.
"No, but really, Kevin's got some important stuff to tell us, so you gotta come to the library. And… it's about damn time, you two. So. Good job." Sam turned to leave, but then twisted back. "Cas… put on your coat. You look naked without it." And he left, leaving the door open behind him.
Dean grinned up at Castiel, stretching a bit to kiss him chastely before grinning broadly. Castiel raised an eyebrow, but slid neatly off Dean's lap before standing and pulling his coat on. He managed to make it halfway across the room before Dean caught him and pulled them together, kissing him sweetly one more time before releasing him completely, except for the fierce hold he kept on the angel's hand. Dean didn't let go, not even when they reached the library, where Sam and Kevin both sat at the table, pouring over books of lore.
Sam looked up as the pair walked in. "Hey, Romeo," he greeted casually.
"Shut your cakehole, Samantha," Dean replied easily, sprawling out in the chair next to his brother as Cas settled in next to him. "So, Moses, what you got for us?"
While Sam grinned, Castiel noted that Kevin looked particularly serious. A tinge on unease settled in Castiel's stomach, and it must have shown in his face because Dean gave his hand a reassuring squeeze.
"You aren't going to like this," Kevin warned. Dean gave a snort –because really, when have they ever liked what the prophet told them– but Cas gave him a look that silenced him while the prophet spoke. "Basically, there are only a few days you can close Hell; the spring and fall equinoxes."
"And those happen when?" Dean asked, already getting a sinking feeling in his stomach.
Kevin confirmed the feeling with his answer. "Tomorrow."
Castiel nodded. "So that means…" He didn't even want to finish the sentence. Just because he'd made his decision didn't mean he was completely confident saying it. Especially when it seemed to bother Dean so much.
"Tonight's your last night with grace."