It's in May that the last of Castiel's Grace shatters.

It's a normal hunt. Normal for the Winchesters Plus One: just a town full of demons, less than an hour from Sioux Falls, and Castiel has his smite on, and an eye to his charges, his friends, his brothers. He places his hand against a new body every few moments and thrills to the clean, magnesium-hot righteousness of his actions when they drop dead.

And then he falls over, weak and shaking and (he knows, right away, he knows) completely human. He crawls out of the fray and shakes under a table there in the diner for long moments, and that is where he is when Dean and Sam finally finish the last of the demons off and crouch to find him.

He reaches for them, and they take his hands and draw him from that place, next to the half-dozen cold French fries and empty sugar packets, and though he cannot meet his Winchesters' eyes, they lead him to the Impala. Dean's hand is hot on Castiel's shoulder and Sam's is warm on his waist, and though he walks with slumped shoulders between them, they walk tall.

In a motel room, Dean pours a generous measure of whiskey into a glass, and passes it into Castiel's hand, as he sits shaking on the sofa. Dean crouches in front of him, and forces Castiel to meet his eyes, and Sam, who seems much bigger than he did a few hours ago, sits on the padded arm of the sofa.

"So what, Cas? Did they freakin' cut you off?"

Castiel sips slowly at his drink because last week he could drink a liquor store but today, he may not be singing Karaoke after a drink this big. And is it a big drink?

Castiel's voice sounds alien.

"I don't know."

"But you have your wings."

If Castiel thinks hard about them he can sense them, twitching nervously behind him. Still he is quite certain they could not carry him, now. He can't teleport and the constant buzz of energy which radiates off his Winchesters is almost entirely silent.

"Cas…"

"I don't know," Castiel answers, and can't it be enough? That he doesn't know? "I need to sleep," he says, as he downs the glass.

He has never slept, before. Dean helps him to strip down to the boxers he is always faintly embarrassed by – they are such a strange item of clothing. Dean arranges Castiel neatly in the centre of the large bed, and pulls the sheet up and over his body, but he shakes and shakes.

"I don't know how to sleep," he admits some time later, knowing full well Dean and Sam are watching him fail in this as they speak in muffled whispers and pretend to research angels.

A few minutes later, Dean's warm body, larger than Castiel's, slips into the bed beside him. Dean rolls Castiel onto his side, spooning him, cradling Castiel against his body, hips molded to hips and knees molded to knees. He speaks nonsense into Castiel's ear. And Sam, who is broad as an ox and shiny and tanned slips in front of Castiel, and kisses his forehead, and his face, tasting the tears Castiel is barely aware have fallen, and the three embrace like that and sleep like that and Castiel starts to thinks maybe he can do this.

They take a few days off the road, much as one does when one's life is irrevocably altered.

Castiel finds that he likes touching and being touched. In the cabin they have rented at a hunter's retreat in what is probably technically North Dakota, Cas leans against Dean's back as Dean slices tomatoes for the burgers. He compares the size of Sam's hand to his own by lining them up and pressing them together. The body that seemed so weak and limited starts to feel like his own, capable, and intensely real, in a way it didn't, before. They watch old films and Dean lets Castiel lean against him, curls an arm around Castiel's body.

Sam and Dean whisper that they can't take him on hunts anymore and Castiel feels so sad until he realizes they are idiots.

"Because I'm human?" he asks, pushing his way into the bedroom he has been sharing with Dean. "Because I'm breakable, now? You, also, are breakable. And you break. Should Heaven have benched you before the… innings?"

"You gotta quit with the sports analogies, Cas, until you actually get sports," Dean says. He is deflecting. He deflects well. He always has. But that night, when Dean presses his mouth to the pulse point in Castiel's throat, and Castiel holds his friend against his body, yes, weak, yes now needing food and sleep and wanting sex and television, Dean agrees, at last, that Castiel is no weaker than he or Sam.

In the next few weeks Castiel learns a lot.

He learns that Dean's hand can unlock him and find his best secrets, that Dean's long, hard cock is a substitute he can happily take in exchange for the Grace he was never entirely comfortable with. He learns that heavenly bodies require no connection with Heaven, and that his wings may not carry him anymore but he can easily snug them around two bodies, or three.

He learns about working hard and getting tired. He learns about drinking too much and getting a hangover and the reason it's better to buy the expensive toilet paper. He learns he is an exceptional bluff and a good poker player and a better pool player. He learns that the sweat that collects in the dip at Dean's collar bone is salty, and sweet, and that Dean likes him to clear it away with his tongue. He learns that having a cold is sort of possibly the worst thing that can ever happen to a person until the time he gets food poisoning, which he promptly decides is worse.

On the bed he always shares with Dean, and occasionally shares with Sam, Castiel learns something else, as well.

The human heart may be capable of immense love but it, like everything else in the world, is fragile.

Castiel's body feels too cold, suddenly, and his breath comes in short puffs. He clutches at Dean's hand though he cannot easily see Dean's face. His lips tingle, and that can't be good.

"Cas," Dean whispers. "Cas, baby, you gotta tell me what you need. You gotta tell me what's going on. Cas…"

In August Castiel learns about health insurance fraud and MRI and passion-fruit flavored jell-o. He learns about counting backwards from ten and only getting to seven and waking up like no time has passed, with staples in his chest and the feeling of cotton wool in his mouth.

Sam and Dean convince Castiel it is okay to take some time out and rest up and get better. So when he is allowed to leave the hospital they find a serviced apartment with a huge spa bath. Castiel leans against Dean's chest, in the bubbling water, and Dean traces his finger over Castiel's new pink scar. He presses a kiss to Castiel's temple. Castiel's feet lie across Sam's lap, and Sam closes his huge hand over Castiel's ankles.

The water is almost unbearably hot, but not actually unbearably hot, and Castiel likes it.

"But it's done, now," Sam says, running his hand over Castiel's calf, shaping it like clay. Castiel shifts into the touch. "You'll be fine, now."

"It's done."

Sam pulls Castiel from Dean's arms and into his lap, and kisses Castiel's mouth, while Dean watches, smiling.

In November, Castiel learns that it is harder to fight demons with knives and fists than with his Grace, and that getting hurt hurts, and that medical science is not an exact science. He falls to the ground in the middle of a fight, clutching at his heart, and he gets up again, and he stabs a woman up though her chin and into her head, just in time for Sam to close his hands around her head and speak his words and when the demon leaves her body, Castiel lands on the ground again, and this time, he cannot clutch at his heart.

Castiel wakes in the back of the Impala. They are driving much too fast, and it occurs to Cas that he should say something to Dean, who is cradling Castiel's head in his lap.

Except that Dean is in the front seat, and driving, and Sam is seated alongside him, map in his hand, trying to convince Dean that taking the next exit will get to the hospital faster than taking another stretch of highway and doubling back.

It isn't easy, but Castiel casts his eyes up, to see the face of the man who cradles him, who has a hand pressed over his heart.

Sandy hair and a beautiful face and big, dark eyes. They might be brown. It is dark, though, which makes it difficult to say for sure. He smells like a hunter, but he has no place here. He presses a finger to his lip, holding Castiel's eyes, and smiling.

In the emergency room, the man sits on a spare bed and his eyes never leave Castiel's. Not when Castiel wants to scream at the injection of another dose of what must be liquid electricity and tears fill his eyes. It is loud, so loud, and nothing they do will make Castiel's heart beat the way it is supposed to. There are doctors and nurses and someone is saying they have to crack his chest and -

The world flickers, and it is just clean and bright and empty, just Castiel lying still and the man sitting on the bed, and yes, now that Castiel can see him properly, he looks familiar. His dusty green jacket and his worn jeans.

It's blissfully quiet, now that they are the only two people in the room.

"Make them stop," Castiel says.

"No," the man says.

"It won't help," Castiel says.

"No."

"Then…"

"They need to know you fought. They need to know they fought."

The man has a ridiculous mop of hair and one of the sweetest smiles Castiel has ever seen.

"It hurts."

"It won't. not for much longer. It's okay, Castiel."

- and the world rushes back, the beeping machines, the doctors and nurses. They shout over Castiel's body and somewhere Dean is yelling at an orderly and Sam is holding him back. But that's okay because the man sits on the extra bed and never drops Castiel's gaze, not once.

Castiel thinks he reaches a hand out but he is not sure. Everything is thick and muddled and much too bright. The voices are muffled, though loud, and everything buzzes.

"Are you ready?"

The man's solemn, quiet voice is the only point of clarity in a chaotic universe.

"Dean isn't ready. Sam isn't ready," Castiel answers, and maybe he doesn't say those words out loud but the man nods, reassuringly, and his smile says he understands. Every injection is agony and Dean's sobbing is the loudest thing in Castiel's head, but Castiel fights anyway.

Time passes, and the man keeps watching, with that soft smile, with his eyes searching Castiel's.

When the world shifts again, it is quite different.

The man crouches by the bed, and he flickers.

"Are you ready?"

Castiel sits up, and climbs down, and turns with regret to watch as they keep fighting for the life of the body on the bed. "I'm ready," he says. They walk away from that place and Castiel pauses in front of his Winchesters, trails a transparent hand over Dean's chest, and presses his hand to Sam's one last time.

"Goodbye," he says. "I'm sorry I couldn't stay."

Near the front doors of the hospital, Castiel looks up, and meets the man's eyes again.

"Alaric Saltzman," he says.

"You remember me?"

"I… yes. You spent much time on our side of the veil, Alaric Saltzman. Such things do not go unnoticed."

Alaric presses a hand to Castiel's shoulder, and Castiel feel tears prickle his eyes. "It's not fair," he says, and it is not quite a whine, but it is not quite not-that either. "I only got a few months."

"You got millions of years, Cas," Alaric answers. "And you guided me into Heaven six times, and I asked… if it would be okay, if I could guide you, this time."

Castiel shivers, though he is not cold. "Heaven is so lonely. Must I be alone for all time?"

Alaric puts his hands in his pockets. "You can share my Heaven. I got bourbon, books. Football on the television…"

"I do not enjoy football," Castiel says.

"We'll get cable," Alaric says.

The world outside should be pitch dark, because it is night, and there is no moon. Still it seems to get brighter and brighter, as Alaric pulls on hand from his pocket and closes it around Castiel's.

"But they'll be lost without me," Castiel says. "Won't they?"

"They'll survive," Alaric says. "It's what they do."

And Heaven might be the nicest place Castiel has been, and his Grace, such as it was, cannot leave him, not from here.