To Change Places

Castiel is still standing by the window, head tilted to one side, listening desperately for the first breath of prayer in Dean's name when it happens. The house begins to shake, the morning light through the window increasing to violent proportions, and the few intact windows of the junker cars shatter like egg shells on pavement.

Sam runs into the room, gun in hand, as the light fades back to normal, as silence and defeat pour over Bobby's house, over Castiel. The older hunter comes scrambling up from his basement at the same time, the demon knife in one hand, a spell book in the other.

"What the hell?" Bobby demands, but Sam is looking out the window.

"Dean," he breathes, voice of awe and terror, and Castiel has to look, though it kills him.

"Michael," the angel corrects, and he's failed, and it's not fair that he can admit such a terrible thing in such a simple way. "They must have found him in a dream..."

"No," Sam says, fierce in his denial. "Can't... how do you know?"

Because Dean can't be here, Castiel thinks, because the angels were always going to win in the end, because even Dean can't out-stubborn the leader of the Host, because Michael and Dean have been meant for each other in a way even Sam and Lucifer have not, because falling is a sin and how could a fallen seraph with a profound bond ever match the unique tie between a vessel and his archangel? "No one's wings are that white," is all Castiel says, though. No other angel would dare try to inhabit Dean, but Sam doesn't know that.

"I don't see them," Sam says, his voice hollow and his eyes burning into the titanic figure in the scrap yard.

They're vast, immense, as white as Castiel's are black, nearly dwarfing the sun in the sky above them, and Castiel feels so small, so lost, so broken. Bobby's hand on his shoulder, trembling but strong, comforts the fallen angel but he knows, oh he knows, what's going to happen next. Castiel wonders if his grace is falling apart inside him, wonders if this is what heart break feels like to a human, wonders what, if anything, oblivion is like.

Sam's tearing the door open, running outside, shouting threats, childlike in his terror, a baby brother, desperate. Castiel has to follow, even though he doesn't want to, because he has to save Sam - Dean would have wanted that, and there's nothing Dean wanted that Dean should not have. He asked for so little, so very little, innocent, righteous things, things that Castiel believes a just God should want for his children, and maybe that's why he's fallen.

"Give my brother back!" Sam's shouting, and all Lucifer would have to do right now is promise to get Michael out of Dean. Castiel wants to die, snatches the younger hunter's shoulder, grips it tight as he did the elder once.

Michael watches this through Dean's eyes, and Castiel doesn't dare to look, not to see his brother behind that vibrant green, not to see the soul he loved chained deep within an archangel's raging grace. He freed Dean Winchester from hell, and now he has failed to keep him free, and humanity has lost. The world will burn, because Sam was not safe, because Dean was not strong, because Castiel was not convincing, not enough.

"Sammy," Dean's voice says, and Castiel jerks his head up, panicking with hope. "Hey, Cas," he adds, when Cas finally meets his eyes.

"Dean?!" Sam is terrified and jubilant at once, and Cas can't wrap his head around it, he just can't. "What the FUCK, man?"

There are chains in those eyes, but Dean isn't wearing them. The archangel is, bound under the kind of will no angel has, no celestial thing can even comprehend, and then Cas realizes. They exist to serve, to worship, to obey. Even Michael, even their almighty general, he follows righteous orders when they're given.

And there's Dean Winchester, a righteous man - The Righteous Man - and he's given an order to an archangel. And the archangel, planning to wear Dean like a pair of shoes, planning to do all the things that no righteous being would do, and planning to hate every second of it while doing it, the Archangel Michael's no match for him. Dean's no angel's vessel, he's more than that. He always was.

Sam looks awed, delighted and, strangely, slightly furious. Well, but to Sam it's his profane big brother, there, shanghaiing an angel. "Seriously man, the fuck?"

"He doesn't want to kill his brother," Dean said, gently. "I think it surprised him that I get that." Dean's so tender when he reaches out to touch Sam's face, and the light that pours over them looks like what a prayer feels like to the angel.

Sam chokes, and then sobs, and the tainted black is pouring out of him, into the ground, and Sam is shining in Dean's light. "I never told you," Dean says, "Dad never said, you never knew. Do you have any idea how good you are, Sammy?"

Sam's eyes are startled, pained, confused, beautiful. Cas wonders if he should go now. "How do you..."

There's a pause, while Dean says nothing, and Sam says nothing either, and the world doesn't dare turn while they don't talk and yet communicate everything between them. Sam's got more kindness and compassion than Castiel's entire garrison put together, so it's no surprise to him that Dean knows this. Dean doesn't do emotions, though, so it's also no surprise that no words happen. Dean just wraps his brother in his arms and in his wings, and Cas decides it's time to slip away. He can't fly, but he can walk back to tell Bobby that the world may not have to end after all.

"Hold up, Huggy Bear," Dean says, and the next thing Cas knows, he's buried in stark white feathers.

His hand moves automatically to slot into the place where his untainted grace lays next to Dean's pure soul. The moment he touches his handprint, there's so much more there, and his grace bursts back into his vessel, filling him up like lightning in a jar. He's shining, too, in Dean's incredible light, and there's nothing they can't do, between the three of them, not now.

"It's gonna work," Sam says, awed, and they turn to walk back toward the house.

"Did you have to wreck everything, you idjit?" Bobby demands, his voice hoarse with ill-disguised emotion as he pretends to sweep up some shattered glass in the yard.

Dean shrugs. "Sorry," he says, and glass goes back where it belongs at his will. "This is gonna take some getting used to," he adds, and looks over his shoulder where the humans can't see.

Those magnificent wings flex in the sunlight and stretch up, up, up, and Cas matches him, doesn't even think about it. Black and white wings caress the sky. "You'll have to teach me," Dean says to Cas. "Landing sucked."

The angel Castiel, known more accurately as 'Cas', amazes himself by laughing.