Summary: It's a split second choice - probably the only one they have left. But Dean makes it, because it's his brother lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU

A/N: I am SO SORRY for the delay of this chapter. What I thought I had handled in a week exploded in my face. Outside (Real Life) circumstances blew up, my schedule blew up, my plans for this story blew up, the other story blew up. Oy vey! Anyway, all of that aside, I am so sorry that you had to wait like two months for this. I would have absolutely held off posting chapter 1 if I knew what was coming.

Reviews: Thank you to everyone who reviewed, favorited/followed, or read last chapter. I'll get around to responding to reviews this weekend.

Question Concerning Slash: This story will not be slash. Though I am a Destiel fan, this tale follows the cannon of recent seasons, with the writers pushing the "Cas is our brother" angle ;) However, I'll be writing as close to canon as possible, so pretty much squint and you'll see it if you want to, just like in the show :D

Chapter Warnings: None! Defensive Dean, Protective/Worried Sam, and a sleeping Cas for all to enjoy.

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Cohabitation

Chapter 2

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His vision returned within the span of one blink; less than the time it took for Dean – Cas – to remove his hand from his field of vision, revealing the completely new road they were barreling down at close to eighty. Sam slammed on the breaks, jerking the occupants in the car forward harshly. Seatbelts hadn't exactly been a priority when they climbed in, which seemed pretty darn stupid now, as the Impala went from breakneck speed to all-out nothing in the span of thirty seconds.

Dean made a pained noise as he caught himself on the dash and the windshield, managing not to fly through the thing probably by angelic-aided strength only. Sam slammed into the steering wheel, strong arms keeping him from completely smashing his face into the top of the wheel. Pain jolting up both arms let him know he probably sprained something at a minimum, and he was sure to feel the bruising on his ribs tomorrow.

The Impala idled in the middle of a back-country road, asphalt lit by the moon high in the sky overhead. There weren't any cars in sight and Sam didn't expect to see any on such a little-used road, which was a good thing considering the car had skidded well into the other lane on its abrupt stop.

A thunderous roar broke the air around them. The explosion made Sam flinch and whip around, desperately searching out the back passenger window. Even as the ground trembled from the shockwave, a plume of smoke and flame flickered over the treetops, climbing into the sky about five hundred feet to the southwest of them. Larger pieces of debris, planks of wood and bits of metal, struck the distant edges of the field that bordered the small road, no less than a hundred feet from the Impala. The sporadic meteors ignited small, lazy fires in the marshy long grass, luckily a fair distance away and not spreading much in the soggy terrain. The smell of burning wood and brush was soon heavy in the air around them, even inside the sealed car, and it took no time at all for ash and embers to begin drifting from the sky. Ground zero for that bomb, with that amount of smoke and destruction, had to be a hell of a sight. There was likely nothing left of the barn or the surrounding woodland and fields.

Sam tried not to think about how they had been in the thick of that explosion only seconds ago. Their latest close call. If the finite trembling of his hands all the way through to his chest was any indication, he wasn't doing a great job of it. The sound of the Impala's passenger door swinging open ripped his attention away from that plume of devastation.

Dean had one hand on the door, half a foot struggling to find its way out of the car to find purchase on the ground. He didn't make it, abruptly giving up the struggle to climb out of the car in favor of doubling over the seat and throwing up on the road below.

"Dean!" Sam shoved his door open, climbing out in a hurry. He moved around the front of the Impala, coming to the side to help support his brother who looked about half a second from falling out of the car and into his own mess.

Which was… oh shit, mostly blood. And he was still throwing it up.

"Dean! Dean, man, hang in there." He propped his brother back up, trying to keep him on the Impala's seat but still hanging over the edge so that any mess made it to the road and not the car. Dean would kill him once he could breathe again if he let the Impala get a hamburger helper makeover.

His brother's head lolled to the side and pale, glowing blue eyes opened slivers to stare at Sam. The hunter immediately took a step back, surprise coloring his body before his mind caught up to override the instinctual flinch. He reached forward, grabbing onto the angel's shoulders. "Cas? Castiel!"

The light faded from those eyes, leaving them terrifyingly empty for a moment before they closed.

"Cas!" Sam was hesitant to shake him in case of internal damage, but he did it anyway, albeit gently. Terror stuck thick in his throat. The blood, that fading light – Cas had said he wasn't sure he had the power left back in that barn, yet he'd sent them and the Impala out of the explosion range. Was that why he was throwing up? And what did that mean for his brother, currently serving as his vessel? "Cas?"

Green eyes cracked back open and Sam let out a relieved sigh that at least one of them was still alive. Dean groaned, raising an arm to brush Sam off his shoulder and the younger Winchester let him. He stood a step back from the car, staring down at his two brothers as the flames and smoke of the burning barn flickered in the distance, visible over the roof of the Impala.

"That sucked," Dean mumbled, voice thick with what Sam suspected was blood. "Don't think Cas had the juice to r-really do that."

Sam nodded along, suspicions confirmed but brow still furrowed in worry. "Is he okay?"

"Says he needs rest." Dean's head rolled onto the back of the seat, eyes closing in exhaustion. Apparently, the angel wasn't the only one. The older Winchester looked like he didn't have it in him to keep his head up, and Sam could easily fathom why. Housing an angel was no picnic, and Dean had a drained, hurting one on his hands. "He get the car with that road pizza?"

"No." Sam would have laughed if he wasn't so terrified and grated raw from the roller coaster of emotion the last hour had been. "No, your car is fine, you jerk."

"Bitch." Dean swallowed and cracked his eyes open once more, managing to look at his brother without moving his head. Despite the fact he sounded liked he was talking through a throat full of pudding, there was real concern and fear in his voice as Dean asked, "You okay?"

Sam nodded, eyes flickering back to the orange and black sky across the field. Dean struggled to turn around and join his brother in watching the plume of smoke through the back window. He didn't have to say anything – Sam could see the same whirlwind of thoughts in his gaze as was going through his own head.

That had been too close. And Cas… Well, it wasn't over yet.

The young hunter walked back around the car, climbed in and put the car into gear once more. She purred in the middle of the road, rearing to get her passengers back to the sanctuary of the bunker. Sam cast a glance at his brother again, but Dean had his head pressed to the window, eyes closed. He was already asleep or soon would be. So Sam put the car into drive and started the long journey back home.

-o-o-o-

All the younger Winchester wanted to do was stop at the first motel he spotted on the road and sleep until he wasn't tired any more, but he forced himself to keep going. The Brits had set that trap specifically for them. While it didn't look like the kind of setup that needed proximity monitoring for success, especially with their advanced equipment and at-will appropriation of satellites, Sam didn't trust the area to be clear. He was not going to be caught unawares for a second time that night, not with his brother in uncertain territory and their angel dangerously vulnerable.

He made it about forty-five minutes down the nearest highway before he could hardly keep his eyes open anymore, resulting in dangerous sways of the car into the other lane and right-hand shoulder. Dean, waking up with the latest corrective jerk of the car, told him to pull in at the next hotel sign. Sam tried to argue – they should get further away – but Dean wouldn't hear it.

"You're practically asleep at the wheel," he muttered without heat or judgement. "We almost died, Sam. Just pull over before you crash my baby."

So he did. They called it quits at a Holiday Inn just off the I-49. By the time they had the keycard in the door and the green light go-ahead, Sam's hands were shaking once more. He didn't even know if it was exhaustion or the delayed adrenaline crash. Dean didn't say much as he pushed into the room and sank onto the first bed without bothering to remove his boots or jacket. Sam pretty much did the same thing, settling on the edge of the second mattress across from his brother.

Dean cracked an eye open. "You sure you're okay?"

"I should be asking you that."

The older hunter closed his eyes with a one-shouldered shrug. "Don't know yet. Cas is alive – we got him out."

"Most of him."

That last moment just outside the barn, seeing Cas's body still chained within, flashed across the inside of Dean's eyelids. The lifeless form of his best friend, sagging against the silver links. That broken down building that was almost their grave, finally going up, taking Cas's vessel – his body – with it. Dean aggressively buried all emotions that sparked up with that singular image. He didn't do emotions and, in this case, he was pretty sure they weren't all his.

The hunter sat up with a groan. He was exhausted and just wanted to sleep till the cows came home, but he knew his brother wasn't going to let them catch the much needed rest before they had this, apparently, urgent conversation. "I don't know what to tell you, man. He's alive."

"And in your head." Sam's expression was soft with relief and exhaustion, even if his voice was tight.

Dean shrugged again, too tired to formulate a real response to that. His body ached like nothing he'd ever felt before, tingling in ways that were anything but pleasant. Like a Magic Fingers on steroids. He figured it was the fallout of Cas using up power he didn't have in order to get them out, like always. But it seemed like tomorrow's problem, one Dean didn't care to think about until then. Right now, he just wanted to join the angel in that oblivion he had slipped into somewhere in the center of Dean's chest, if the weighty feeling dead center in his sternum was any indication.

"We'll figure that part out later."

Sam nodded, realizing there was nothing they could do about it right now anyway, and the two needed to rest before they toppled over. He toed off his boots and made the effort of pulling back the covers of the bed, even as his brother collapsed back with no such priorities. Reaching for the flat pillow, Sam paused, staring at his fingers. They were still shaking.

"He's really okay?" The question was quiet and frankly terrified. It had been too close. And that bomb…. Death may have become something of a dalliance for the Winchesters, Castiel included. But there had been something about that churning vial of grace, rigged to blow, that Sam knew there would be no coming back from.

Cosmic consequences.

He glanced over at his brother, who was staring at him with an identical expression beneath the exhaustion. Dean was hearing the same echoes of Billie's warning. His eyes, locked on his brother, said he understood Sam's fear all too well.

"He's okay, Sammy. Not talking much – think he's wiped out, man. But we got him."

The younger Winchester nodded again, maybe a little too quickly. He curled into the bed, back to his brother and their angel, and sunk into a thankfully dreamless oblivion.

-o-o-o-

They made it back to the bunker late the next afternoon. They'd slept in longer than either hunter had intended. Well, Dean had. Sam was up a sparse five hours after they'd called it, which was still a lot more sleep than he'd expected to get. He wasn't quite like his brother – he liked more than four hours a night. However, what he liked and what his subconscious allowed him were two very different things.

Dean, however, slept another three hours after Sammy started putzing quietly around the room. He slept on through his younger brother showering and dressing, researching angelic possession, grace restoration, and vessels, and going for coffee and breakfast. When Dean didn't rouse at the smell of grease and eggs, Sam started to worry.

But the hunter jumped awake the second Sam's hand landed on his shoulder, eyes shooting open and hand pressing a hunting knife to his brother's chest in one fluid motion. Sam, having experienced that sort of wake-up call from both sides on more than one occasion, stilled until Dean recognized him and collapsed back into the bed with a groan, knife falling harmlessly to the mattress.

He was up a few minutes later, scarfing down breakfast like he hadn't eaten anything in a week and itching for a shower to wipe off the grime of the previous night. For all intents and purposes, he seemed completely normal, but Sam kept an eye on him all the same.

They got on the road an hour later. Cas was still sleeping, his brother confirmed it as soon as Sam asked how the angel was doing, and that was that. They spent most of the day's drive in silence. The younger of the two tried to talk options, but Dean shut him down almost immediately. They needed to wait for Cas to wake up. Sam was well used to dealing with his brother's concern taking the form of irritation, so he didn't push it.

Dean took most of the driving, snubbing Sammy's offer to share the load in favor of bringing up his repeat offenses against Baby's brakes and treads the previous night. Eventually, with a shake of his head and a lot of eye rolling, Sam stopped offering.

They were barely down the stairs into the War Room when Dean announced he was taking a nap. Sam faltered on the final stair, almost eating floor before he caught himself and stared after his brother in equal parts surprise and worry.

"Dude, you just slept like eight hours."

"Yeah, well, I drove the last three," the older Winchester countered obnoxiously. Sam didn't bother arguing that he'd offered to share the drive. Instead, he watched with a furled brow as his brother waved him off and disappeared down the hallway to the dormitory wing.

The hunter stood in the center of the silent bunker, worry gnawing at the newest block of dread forming in his stomach. With a sigh, he dropped his bag on the table, dragging his feet to the nearest chair. He collapsed into it wearily, eyes still glancing towards the door Dean had disappeared through.

Now that they were home, the tension of the last twenty-four hours finally slid off his shoulders, though that tense ball in his gut fought damn hard to hold onto it. But they were safe, and the relief of it was a weight off Sam's chest he hadn't realized had gotten so heavy. The young hunter buried his head in one hand when it finally hit him that he could breathe again. His stomach argued otherwise, but he knew it was a slow-building dread. The kind that came with 'shit's coming but it isn't here just yet'. His brother was safe, their best friend was alive in a manner of speaking, and they were, however temporarily, out of reach of the British Men of Letters.

Cosmic consequences.

Sam closed his eyes and pinched the bridge of his nose. He was depressingly familiar with the signs of early PTSD. Hell, he could tell the difference between trauma and full post-traumatic stress. While he knew this was the former, it posed no less danger or taxation to the mind and body. Dean was probably dealing with something similar, on top of housing an angel.

If I decide to do something else stupid, I'll let you know.

Sam pushed out of the chair, rubbing at his arms and the itching need to do something. He tried not to let the worry eat at him. Cas was hurting, completely drained, and from what little he could get out of Dean, it sounded like the angel may have sapped up a bit of his new vessel's energy as well to get them out of the explosion range. While Sam was thankful they were alive, he worried about the lasting effects on both his brothers.

So he dug into the research. Despite Dean's request to let it be until Cas recovered some, Sam saw no point in waiting. He immediately ransacked the library, making several looming stacks at the center table and tucking in. They had endless books on angels, research conducted by the Men of Letters and collected data from centuries of observing the supernatural. Sam had been through a healthy majority of it several times before, during the stint with Gadreel, Metatron, closing the Gates of Heaven and Hell, and all the other various divine problems they'd dealt with over the years. He knew that most of that collection had little about angelic possession itself. However, he hadn't been focused on this kind of problem the previous times he'd been through it.

Maybe he had missed something.

Dean might want to wait it out, but Sam knew that was little more than his brother procrastinating what could be an ugly truth. Cas had said he might not be able to leave, and if that ended up the case then the younger Winchester wanted a head start. If the angel wasn't able to eject himself from his brother or find a vessel on his own, they'd need a backup plan. Given how much research there was to sift through and that there was no guarantee what they needed was even there, Sam had a lot of work ahead of him.

His brother and their angel could thank him when they'd inevitably come to realize how difficult living with another person in your head was.

-o-o-o-

Sam stumbled into the kitchen in the early hours of the evening for a coffee refill, only to find Dean in the kitchen cooking up a storm. His older brother greeted him with a grin, flipping burgers in a skillet as he juggled onions and mushrooms in another along with cutting slices of cheese off a cheddar block for melting atop the burgers. All five of them.

"Dean?" Sam couldn't exactly hide his concern. Worried curiosity, really. "Are we expecting company?"

Maybe mom had texted him and was on her way by.

"Huh?" Dean glanced down at the five patties and shrugged a little sheepishly. "Woke up starving. I'm famished, Sammy. I figured you'd want one or two, though."

Sam stared at his brother incredulously as he slid into one of the island chairs. The image of his brother scarfing down breakfast that morning came to mind. "You're making three burgers for yourself?"

Dean had the decency of at least looking like a scolded child amidst the defensiveness that flashed across his face. "I'm hungry.

"And…that's not freaking you out?"

The older Winchester rolled his eyes, shooting Sam a warning look. "It's got nothing to do with Cas, alright?" At his brother's raised eyebrows, he amended, "It's got nothing to do with an angel possessing me. Cas just ate through a lot of juice. We need some replenishing is all."

The fact that it was a burger, Cas's famine-worthy craving, was coincidence as well, Sam was sure.

The younger of the two brothers didn't push the matter further, just set his coffee cup down and climbed back off the stool to grab plates and beers. He didn't want to be the bad guy here, he really didn't. He loved Castiel as much as he loved his brother, but at least one of the three of them was being purposefully blind about the situation.

"What are we going to do about him?"

Of course, charging a problem with a battering ram never worked when it came to Dean. All you got in return was your own battering ram back to the head. Approaching problems that his brother didn't want to talk about sometimes took a more subtle, manipulative approach. It wasn't something Sam was a fan of, but as a kid whose childhood goals had been becoming a lawyer, he was damn good at it.

Green eyes avoided his gaze, glaring down at the stove and sizzling burgers as though they were what had gotten them into this mess.

"Dean?"

"I don't know," his brother finally caved, giving the patties an unnecessary flip to avoid looking at Sam. "We're just gonna have to wait until Cas wakes up. See if he can even leave, or if finding him another vessel is pointless."

"We can't just leave him where he is." This was what Sam had been worried about as he watched his brother all day. It was one of the two worst reactions Dean could have, both of which Sam had been fearful of, but fully expecting. His brother wasn't a complicated guy, not when you got to know him. Things boiled down to guilt or anger with him, and all the actions and choices that followed pointed to which base emotion had tripped him up.

If it had been anger, Dean would be brooding and pissy, itching to get Cas a new vessel, frustrated the angel had been captured, and impulsive in the way they went about every next step. It would be a cover for how afraid Dean was, afraid of what had almost happened to their angel, afraid of what still could, and tired of their never-ending crap lives. But it would have manifested itself as anger, irritated and abrasive towards everyone and everything. But most prominently at the angel himself.

They'd been there not that long ago, after all.

Cosmic consequences.

In some ways, Sam was glad it hadn't been an Angry Dean he'd woken up that morning. For several years now, Castiel had been struggling with belonging and feeling at home in a family that wasn't blood. Sam knew he and Dean's actions were partially responsible, and he had thought they were doing better. But Angry Dean had a bad habit of undoing all their hard work.

Guilty Dean, on the other hand, had the worst martyr complex Sam had ever seen. Whenever his brother fell into that mode, Sam ended up toeing the edge of his own limits, waiting for Dean to throw himself at the first grenade they found. And sometimes second, third, and fourth. Unfortunately, in this case, that grenade would be Cas, and they were both going to get blown to smithereens in the process.

Again.

"Come on, man," Dean was already countering, pulling Sam from a depressing spiral of thoughts. Sam focused back in on the kitchen, where his brother was giving him the stink eye that said he was approaching his own limits on this conversation. "The guy is hurting. Can we at least wait for him to heal up before we kick him to the curb? Again?"

Sam watched his brother's eyes drop away and back to the stove, trying to hide the regret and self-loathing that flashed across his face. Yup, definitely Guilty Dean.

"We're not kicking him to the curb. That's not what this is about."

"Then what is it?" Dean's knuckles were whitening around the spatula in his hand, images of a wrecked angel-turned-newly-human staring at him in dismay as he all but threw him out when the guy had nothing to his name. "Because it sure as hell sounds like you wanting to kick him out."

The younger of the two jammed a finger in his brother's direction, eyes sparking with their own fierce protectiveness. "Do not lob your guilt on me, Dean. That's not what this is. I'm not kicking Cas out."

Dean visibly bit back a response, jaw clacking shut as he looked away, face reddening. The older Winchester wanted to yell, to defend a choice that had never been a choice at all. Only he knew that was bullshit. There had been a choice: Sam or Castiel, and Dean had picked one, loud and clear. He knew that he and Cas had never really cleaned the air about that. He had never truly cleared the air. Maybe that was why he was all for Team-Let-Cas-Stay, when being reasonable and accommodating was usually Sam's gig. Dean cleared his throat, counted to a number a lot higher than ten, and looked back at Sam with more reason in his expression. "Then what is it?"

"I'm talking about you being a vessel right now; the very thing we spent years fighting against. I know how hard you fought being an angel condom. Hell, you changed destiny just to avoid it. And right now, you are way too calm about all of this."

Dean drew his head back, affronted. "Sam, it's Cas! Will you stop talking about him like he's one of those dicks! It's Cas."

"I get that, and I'm glad that we saved him, Dean. Thrilled, man. Cas is our best friend – he's family, and I can't imagine life without him." Sam had to take a deep breath to hide the cracking in his voice as memories of Cas's body, chained up in that barn, flashed across his mind. He settled fisted hands on the countertop to hide the slight tremor that returned just thinking about the close call. He didn't need Guilty Dean turning mother hen on him when this was about Castiel. "But we can't just ignore that you're basically being possessed, even if it's Castiel doing the possessing!"

The older hunter grit his teeth. He spun around to turn the burners off aggressively and start divvying up burgers onto plates. "It's fine. For now," he tacked on over his shoulder as Sam immediately threw him a look. "Let's just let him heal up, then we'll worry about the rest, okay?"

Sam was hardly appeased or in agreement. He was still convinced Dean was fighting too much guilt and self-imposed penance when it came to doing right by Cas to see the situation for what it was. But Sam could see it. He'd been a vessel before, twice, and while Castiel was nothing like Lucifer, but angelic possession was still possession. Sam understood the lack of control that came with sharing a body, even the symbiotic living that came with an angel like Gadreel.

He knew his over-protective, controlling brother was not going to handle forced cohabitation well, despite whatever current contentment he had guilted himself into.

-o-o-o-o-o-o-o-o-o

A/Ns: Apologies once more for the ridiculous delay on this chapter! I'm not going to stick to a posting schedule for this story, since I'm not confident how my writing calendar looks over the next month. Hooopefully I'll get another chapter up in the next one to two weeks.

Thank you for waiting this one out, and I hope you enjoyed!

Sam's Behavior: For those of you thinking Sam's being a bit of a dick towards Cas in this situation, he's just not getting his point across well yet (ah, brotherly communication. It's the best). He's got a good point that Dean's just going to have to learn the hard way.

Review: Please review. Comments, critique, and encouragement help feed the muse! Unfortunately they can't help my busy schedule, but it's still better if the muse pokes and prods me continuously to make/find/steal time.

Up Next: Cas finally wakes up, Dean gets to deal with a roomie in his head he's never had before, and Sam puts his thinking cap on for solutions to their newest dilemma. Damn, but he'd really hoped to never have to use that grace extraction needle again.