Pairings: Dean/Castiel
Rating: PG-13 for language
Word Count: 2454
Disclaimer: These characters do not belong to me. I am making no profit from this fanfiction.
Warnings: Drowning, near-death experience (nothing graphic)
Author's Notes: This is my first Supernatural fic, written because shut up I wanted it. If you wanna give me constructive feedback that would be wonderful. This is a canon divergent from 9.03

Dean doesn't see Cas go under.
They're out hunting, just a basic job to pass the time while Kevin tries to figure out how to fix Heaven using info from the angel tablet. Sam is still on the mend, and Zeke's still not letting Cas stay at the bunker, but they're trying. Dean tries to visit Cas as often as possible, whenever he can think of any sort of excuse to escape the bunker, which was feeling more and more like a prison as everything he's hiding festers in the air.
Being with Cas is better. Marginally.
Cas still gets that hurt look in his eyes whenever he thinks that Dean isn't paying attention, but he seems to respect Dean's scattered explanations and is resigned to his fate. He sucks at playing human, but he's doing alright, or at least he tries to pretend that he is. Dean isn't entirely fooled, but there isn't that much he can do about it.
Today was different than their usual routine - mostly when Dean was with Cas they just hung out, catching up and avoiding dangerous topics of conversation. Today, however, Sam had called, asking if Dean was done with the salt-and-burn that he'd said he was going on two days ago. There was another case close by, Sam had said, maybe Dean wanted to check it out whenever he wrapped up with the ghost?
Well, Dean figured, might as well get some actual work done while he was out. It would be nice to take on a case by himself, just as a distraction. What he hadn't expected was Cas's insistence that the fallen angel accompany him.
"Cas, really, it's fine, man," Dean had said. "I know you're not used to the whole human thing get, I don't want you to feel obligated to go with me if you don't want to. I've been on plenty of solo hunts, I can handle it."
It wasn't that Dean didn't want Cas to go. Hell, he actually wanted it more than he was readily willing to admit. Having Cas there would mean extra backup, and he trusted Cas. Sometimes more than he trusted Sam, even, which should terrify him, but didn't. After everything, it felt right, made sense.
But Cas was human now, breakable, and the last time Dean had asked him to go on a hunt Cas had practically begged Dean to just let him be, let him live his normal human life and respect what Cas was trying to build here. And Dean had tried. Had really tried. He'd even tried not to go back, just to let Cas go, but the idea of saying goodbye had felt so wrong, so messed up and backwards and twisted, that Dean had felt his resolve slipping the second he drove away.
He was back less than two weeks later.
But Cas had never been on a hunt with him, after that. Dean had never taken one on in the middle of his visit, and Cas hadn't asked or offered. This time, however, Cas seemed determined, and Dean was fairly powerless to resist.
"Fine," he'd eventually snapped. "Just… stay out the way and don't get into trouble, alright?"
Cas narrowed his eyes slightly. "Dean, I have been alive for longer than your limited psyche can fathom, and I have been a warrior for nearly as long. I highly doubt that the restless spirit of a deceased human is going to be a terrible threat."
Okay, so apparently other angels? Scary. Ghosts? Not so scary.
"Alright, okay. Size-of-the-Chrysler-Building, I remember," Dean huffed, raising his hands defensively. "Just don't underestimate it."
Cas actually rolled his eyes then. Actually, physically rolled his eyes at Dean, who had to turn away because the gesture was so human that it made the hunter feel almost ill.
Sam had already done most of the research, so now it was just the simple matter of going to the burial sight and burning the bones. Less interesting than Dean would have wanted, but since Cas is with him, he isn't really complaining.
"I think the bones are buried in a family cemetery," Sam had said over the phone. "This guy's family is like, super old. They have this giant creepy mansion next to a lake, and their family cemetery is on a small island in the middle. They probably have a boat to get over there, just look around." Dean could feel his brother's smirk through the phone. "Otherwise I guess you'll have to swim."
"Yeah, yeah, thanks Sammy. Middle of October, no thanks. W- I'll get it done. See you soon." He didn't give Sam time to reply, just snapping the phone shut roughly and telling Cas the game plan.
There wasn't a boat, but the island was actually quite close to the land, and in recent years the family had extended the dock into a small bridge. Dean had grabbed his bag out of the trunk of the Impala and nodded to Cas, and the two of them crossed the bridge cautiously.
Of course, nothing was ever simple, and the spirit of Mr. James R. Burklin clearly did not want to be put down easy.
Dean was hit first, having led the way, and the invisible force threw him off his feet as soon as his boot hit the soft, muddy ground of the cemetery, which was about two steps away from the end of the bridge. His head slammed against a headstone, which was always pleasant and had his ears ringing.
Which is how he missed the ghost turning its attention to Cas, who was still on the bridge, missed it shoving at Cas with invisible fingers until the recently fallen angel tumbled into the water.
Dean hears the splash but doesn't connect it with any particular event, not right away. He sits up and shakes himself, looking around, looking for Cas. He sees the sloshing of the water against the dock, and the bubbles rising alarmingly to the surface of the choppy black surface, and understands.
Cas hasn't come back up.
The goddamn angel doesn't know how to swim.
Dean is on his feet in an instant, fuck his pounding skull, shucking his jacket aside as he slips onto the bridge and wrestles his boots off, because he's not gonna be able to drag himself out of the water with all his clothes iand/i Cas. He's still got one shoe on when he's shoved from behind, and he fails as he tumbles into the freezing water.
Goddamn motherfucking ghosts and Jesus that's cold.
He fights to the surface and gasps in a few breaths, looking around frantically for a sign of Cas, but the water is completely black, betraying him. Panic is settling low in his stomach, crawling up his spine. He dives under the water again, fingers reaching blindly, just looking, searching, and he goes up for breath and under again, deeper, have to find him have to can't see where -
There, cold cloth brushing against his fingers and he latches on, feeling the weight behind it, and tugs, shoving upwards. He breaks the surface of the water with a gasp and a cough, and drags both himself and Cas halfway out of the water, gagging on the freezing liquid trapped in his lungs.
"Cas," he chokes out, leaning over his friend and pressing numb hands into the cold shoulders. The angel's face is slack, lips pale and blue and dead. "Cas no, not again man you promised me, you fucking promised -" Dean shakes him, but Cas, the traitor, doesn't move, doesn't breathe. Dean doesn't wait, can't even feel what he's doing anymore, but he's had enough medical training that he just runs on instinct. Tilt up the head, listen for breath, two rescue breaths, listen again. He repeats and gets nothing. Cas's lips are cold and slightly chapped and so lifeless that it feels like Dean's lungs are collapsing, like he's the one drowning instead of Cas. When his fingers go to Cas's throat he finds no indication that the other man's heart is still beating, just flat, white skin and this was something Dean never wanted to experience again, would have paid anything not to see, but apparently God, wherever the bastard is, wants Dean to suffer it over and over.
Dean pushes Cas's jacket out of the way and started shoving at his chest, trying to stick to the standard thirty compressions but having a hard time keeping his count right because he just needs Cas to open his fucking mouth and breathe. He tells Cas so, chanting the angel's name and begging him and threatening him and please, please Cas wake up I need you man please please please -
Cas's body suddenly convulses, and Dean jerks back as the fallen angel gasps and gags up what seems like too much water for one pair of lungs to hold. Dean holds Cas up and helps him lean over, rubbing his back and patting it, trying to help him get the water out of his system. He still feels more panicked than relieved as Cas slumps back to the ground, breathing hard and twitching.
"Cas, Cas man talk to me, say something," Dean pleads, leaning over the angel and cradling Cas's head. He check's Cas's pulse again, even though he can hear the other man breathing, because he needs to feel it, the too-fast flutter of it against his fingertips. "Cas," he says again, pushing against the angel's shoulder roughly.
Castiel opens his eyes and looks at Dean blankly, his chest heaving. He blinks, focusing, and when his voice comes out it's no more than a croak. "Dean."
The relief that punches through him is so intense that Dean actually groans, his eyes falling shut as he presses his forehead against Cas's. "What the fuck did I say about dying on me, man?" he mutters, the adrenaline draining out of him and leaving him exhausted. He doesn't realise he's shivering until he feels Castiel's hand come up to touch his shoulder lightly, and then he's shaking so hard that he feels like he might rattle apart. He draws back a bit and opens his eyes, and Castiel is staring at him with an expression that is equal parts awed, terrified and confused.
"Did I…?" he asks, his voice small and cracked from coughing and choking up water.
"Yeah, you fucking did," Dean says, pulling away and practically falling backwards, sitting down on his ass and running both hands over his face, unsure of whether the dampness he finds there is from the lake or something else. "You fucking promised not to and you did anyways, and you are so freaking lucky that I know CPR, you bastard."
Cas is sitting up now, wincing and using his hands to support himself. "You are angry."
Dean just looks at Cas for a moment and then pushes himself to his feet, swaying a bit before shaking his head and reaching a hand down towards Cas. "C'mon, we're done here. Fuck this ghost, I'll call someone else to deal with it."
Cas is unsteady on his feet, and Dean keeps one hand on the former angel's shoulder as they make their way back to the car. A hand clenched in his jacket stops him after he slams the trunk to the Impala closed. He turns to glare at wet figure beside him, feeling tense and wronged and his hands are still shaking. "What?" he bites out.
Cas winces, letting go of Dean's jacket. "Dean," he starts, and pauses, taking a breath. "Dean, I am sorry. I am unsure of why you are so angry with me, but I know that I have upset you. I will be more careful in the future." He frowns slightly. "I have again… underestimated… this body's weakness."
Dean stares at him for a moment, and then he leans into Cas's personal space and points an accusing finger in the other man's face. "Don't you ever, ever do that to me again," he says, and he doesn't care if he sounds pissed off, because he is. "I can't keep watching you do this, I can't, man. It's too much." He uses the hand that was pointing in Castiel's face to run a hand across his mouth, turning away slightly to gather himself before looking back into those devastatingly blue eyes. "Just, just don't, okay? You, you've got to just gotta be more careful, man, I don't know if I can -" He stops talking then, because his throat betrays him and closes up and he just has to stand there breathing through his nose and looking away as he tries not to be such a child about this.
"Dean," he hears Cas say, and the sound is all affection and worry and regret smashed into one syllable, and then Cas is pulling him forwards and Dean just falls into it, smashing his face into Cas's collar and clutching at the other man's back, curling his fingers into the broad shoulder blades as if he can hold Castiel here with him using only the tips of his fingers. Cas's hands are running across his back in soothing circles, like Dean is the one that's broken here, instead of Cas.
"I am so sorry, Dean," Cas says, and Dean's not sure what Castiel is apologising for, because it sounds like he might just be saying sorry for breaking his promise, or maybe for everything. His hands are trying to rub away the shuddering gasps that Dean is letting out, and the hunter wants to pull away and say that he's fine but Cas had just been lying there and he'd been dead fucking again and if Dean has to see that one more time he's just gonna fucking break.
So instead he just holds Cas even tighter and says "If you ever do that to me again I'm gonna kill you myself, hear me? I will fucking follow you to Heaven or Purgatory or what the fuck ever and I'll - I'll fucking -" Dean stopped talking, just pressing himself deeper into Cas's neck and breathing in the smell of lakewater and off-brand shampoo.
"I promise, Dean" Castiel says, and it sounds like he means it, and Dean's gonna fucking hold him to that. He untangles himself from Castiel with a reluctance that borders on actual pain, and turns away with a "yeah, you better" before getting into his car and staring out the window until they get back to the motel.
He leaves the next morning before Cas wakes up, and he can't say goodbye because if he does he doesn't think he'll be able to leave.