"Cas." Dean's voice is hoarse. He hasn't really slept since Cas flew past their failed attempt at angel proofing. It's killing him. It's like Sam and the demon blood all over again. Only Sam he could stop. Sam he could track down and find without having to use a spell and a ritual.

But Castiel is an angel. He can crush Dean like a grape with just a more-intense-than-usual look. He can hide away in Heaven until Dean dies of old age. Hell, for all he knows Cas has found a way to make their summoning rituals not work on him.

There's very little Dean can do to keep Cas from flying away. Fool him once, fool him twice. Cas is not falling for the holy oil stunt again.

If Cas is here, it's because he wants to be. If Dean can see him, it's because Cas wants him to.

"Hello, Dean."

If Dean gets away with this…it will be because Cas lets him.

"Wasn't sure you'd come." He lies, trying a smile and failing.

Cas' lips twitch upwards. It's a sad smile, and in his eyes fight warmth and shame as he meets Dean's. "I suppose telling you not to lie to me would be…hugely hypocritical, at this point."

Dean does smile this time. What a couple of sad sons of bitches they are.

"I still do it better than you." He counters.

They stand in silence for a long moment, a million things that need to be said struggling to come out but ultimately cowering away.

"You can take the sword out, Dean. I know you have it."

Of course he does. Dean chuckles at his own stupidity, cursing his shaky hands as he reaches into his jacket and pulls the angel sword out. The sword Cas gave him all those months ago for him and Sam to be able to defend themselves when he's with them. When he can't risk his ass again to save theirs.

"Then you also know why I have it." Dean is trying to scare him off. He doesn't want it to end this way. He can't let it end this way. But he has to. Because he won't have Sam or Bobby do this. Because if someone is going to, it's gonna be Dean. "So why are you here, Cas?"

There is a pause before the angel answers.

"Because I was wrong. It is broken." Dean can swear he hears Cas' voice breaking, but the angel is looking away from him now, so he can't be sure. "Only it's too late to fix it now."

There's nothing Dean can say to that. Because lying to Cas for mere reassurance is useless. It won't help him. It won't help either of them.

"You were family once."

Castiel looks at him, and Dean thinks that's the widest smile he's seen on the angel's face. Even if his eyes are shinning to bright, and his voice is choked up when he speaks.

"I know," he swallows, "And I…can't tell you how proud…how happy it makes me that you ever thought of me that way."

Dean is the one to look away this time. Because if he loses it now, he will never get the nerve to do what needs to be done. Dean knows Cas has done everything he can to keep the world going one more day. He's shoved the thought of consequences away and done everything within his power to defeat Raphael. But in saving the world, Dean has lost his best friend. But Dean's scared -he's fucking terrified- of what Cas will become once everything finally gives way and the tight thread that's keeping him together snaps. Dean is not worried for the world. He's worried for Castiel.

Cas has become a danger to himself. And Dean knows he'll be damned if he ever lets Cas turn into that broken shell of an angel that Dean sent to his death in a future that he thought he'd managed to avoid.

And Dean can tell that Castiel knows this too. The angel looks tired. Exhausted. Resigned and pleading for the end at the same time. It makes him think of Lenore and how she couldn't bear to live with what she was becoming.

Maybe that's why Cas killed her.

Maybe that's why Cas saved her.

Maybe now it's Dean's turn to do the same for him.

It's Castiel who takes the final steps that close the space between them.

"Run, Cas." He begs, not daring to look at him in the eye. Stupidly hoping that maybe Cas will be selfish for once in his life and save himself. "Please."

"You know I can't do that." The angel's voice is soft. Understanding. Pleading.

But Dean can't find the strength to lift the sword, and his knuckles pale as he clings to it like a lifeline.

He feels a hand on his own, firm but gentle as it guides the blade to the angel's chest. A contradiction that describes Castiel so perfectly that Dean suppress a laugh that he knows would have come out like a sob.

Dean's free hand reaches up of it's own accord and grips the lapel of that stupid, dirty trench coat, and he glares at Cas because it's the only way he can be sure the tears won't betray him.

Castiel squeezes his hand before slowly moving it to Dean's shoulder; right over the brand he left upon saving him from Hell. He looks at it wistfully for a moment before turning blue eyes at Dean.

"Thank you."