AN: a sastiel pirates!AU. Does what it says on the tin! Originally posted on my tumblr (itshellfiredean). This will be multi-chapter.

Hope you enjoy this! All spelling mistakes and/or historical inaccuracies are my own. :)

Waves lashed the side of the Impala, crashing loudly into the ship's old wooden sides and drowning out the sound of metal clashing on metal, and gunfire. Both the crew and the pirate vessel itself were suffering a beating unlike any other they had ever experienced.

They certainly hadn't intended to run into the HMS Celestial. Captain Winchester had been adamant, though, that they wouldn't let the rumours of naval ships in these waters discourage them from their path: on their way to a small island to investigate a supposed haunting that they'd been hearing about from every two-bit sailor that had ever propped up a bar, Dean Winchester had insisted that they take the shortest possible route. He didn't scare easy, after all.

His first mate – his brother – had been a little more reluctant to take this route. But, raised on the high seas under first the watchful eyes of his father and then his brother, who had inherited the ship, he trusted the latter to get them to it with the minimum of trouble, as he always did. Dean always pulled through. They'd never been caught, and they were legendary both with the navy, and amongst other pirates – for better, or for worse.

The Impala, and her crew of Winchesters and vagabonds.

However, this time it didn't look like they were going to get away: they were losing the fight, that much was obvious to Sam, as he fought off an enthusiastic naval officer, who was trying to lodge his sword into Sam's ribs even as he assessed the situation. He kicked the officer in the stomach, sending him rolling down the stairs, onto the deck, from where he stood at the ship's helm.

Next to him, his brother was desperately trying to steer the ship away, but to little avail.

"We're getting slaughtered!" Sam informed him in a yell, fighting with the sound of fighting and the elements to be heard. Dean frowned back at him, casting his gaze around, and cursing loudly.

"Fuck it," He said, and drew his sword, abandoning the helm to help fend off the onslaught of officers making their way onto the Impala via makeshift gangways."Weigh anchor!" He yelled, then looked around - every single member of his crew was busy defending both him and themselves. "… Someone," He added under his breath with a wave of his hand that had Sam staring after him incredulously, momentarily forgetting how deep in the shit they were.

Dean ran into the fray, leaving Sam to look at the devastation: in his heart of hearts, he knew it was too late. They'd really screwed the pooch this time.

Bobby was backed into a corner, blood from his head running into his beard; Rufus had fallen on his ass unceremoniously, dropping his weapon, and was cornered, too; Tamara and Isaac were standing back to back, surrounded. Other crew were also quickly being subdued: either knocked out, or surrounded, with a sword at their throats or a gun to their head.

Sam followed his brother, as he yelled at them,
"Right! Which of you sons of bitches is in charge here?!" He garnered the attention of the vast majority of his own crew, as well as the opposing crew.
"I believe that would be me," A voice called above the commotion. From across the gangway, a tall, pompous man with a white wig and ostentatious hat appeared. He was slightly overweight, and wearing the sort of smug smile that Sam knew would wind Dean up straight away. He must be the Captain, then. Or a Commodore, he thought, his stomach dropping.

Behind him, another man scuttled, boarding the ship just after the first. He wasn't much to look at: a typical, bureaucratic naval higher-up. He was a little older than Sam, with a little scruff, and a black wig. Rather than address Dean, as the first man was doing, he chose to direct his calculating stare at Sam.

He must be the First Mate, Sam gathered, returning the stare with his own hateful glare.

The navy had stolen their father – he'd traded himself for the lives of his sons, after all. He was deemed a bigger threat than them, at the time, so the authorities had thought all their Christmases had come at once. However, in the years that passed, it was obvious that Sam and Dean Winchester were actually much bigger troublemakers than their father: stealing from merchant ships, killing men they perceived to be evil or in some way 'supernatural' (though no one really believed that crap they and their crew spouted).

"Commodore Zachariah – and of course, I know who you two are. The famous Winchester brothers. Isn't that right, Dean?" The pompous man presumed.
"That's Captain to you, jerkoff," Dean spat, keeping his sword raised aloft.

Zachariah laughed. His first mate shifted without changing his blank facial expression, making Sam frown. He was going to keep an eagle eye on this bastard, that was for sure.

"Hardly … Your crew are subdued, and you are captured. We'll be taking control of your ship. You shall all hang for this, and my career will be made," Zachariah's self-satisfied smile just widened as he spoke; Sam watched as Dean's scowl deepened in ferocity, growing darker and darker. He was about to do something stupid, probably.

"You and your precious … Brother," He continued, looking for the first time at Sam; a quick up-and-down, causing his lip to curl in revulsion. Sam's frown increased, and he cocked his head to the side, eyes narrowing. "You'll be dead this time in a month – nothing more than a warning to your fellow pirates, your rotten corpses hanging from cliff sides,"
"You can try and stop us – a bunch of your pals tried in the past, and, well … Didn't go too well, did it?" Dean smirked. Sam smirked too, when he recalled the last time a naval vessel had tried to attack them: not only had they fought them off, they'd also ransacked the ship for any valuables, chucked most of their crew in the sea, and left the captain – a vicious man named Captain Uriel – tied up in his quarters for days, until the ship drifted close enough to St. Mary's naval port that somebody spotted it.

Zachariah's smile faltered, and twisted into an expression of the deepest loathing: he paced across the boards that made up the ship that had been handed down through generations of Winchesters, until he was as close as he could get to Dean without being impaled on his weapon. Curiously, the First Mate stayed where he was; Sam, too, felt he had to stay put, and watch him: he could do anything. He had to focus, even though Dean was being threatened, and there wasn't much he could do about it right now.

"Perhaps I'll hang your brother first – try and make sure his neck doesn't break, so he's strangled to death, kicking his freakishly long legs, gasping for air …" Zachariah began, circling around Dean, whose face reflected Zachariah's malice, as he tracked the commodore's movements. "… And then, I'll leave his body out for the crows – they're peck out his eyes, eat his skin … I've seen it, it's not pretty," He paused, arriving back in front of Dean, and in view of both crews. "Only then – after you've seen your precious brother killed and mutilated – only then will I allow you to die,"

Dean looked down at the deck – and that was when Sam knew he was on the cusp of jumping into action. His hand flexed on the hit of his own sword, and he studied his rival First Mate with interest. The other man arched an eyebrow at him curiously. Sam didn't respond in kind.

"Nice idea … Here's my response," Dean replied, and made a swipe for the commodore's neck. The older man was surprisingly spritely for his stature, and dodged it – and that was all Sam saw, before he himself was leaping into action, attacking the blue-eyed man in front of him with gusto.

He thrust forward, making a stabbing motion with his right foot forward. A hair-trigger reflex on the part of the Celestial's First Mate meant that he had drawn his sword and deflected the attack in a matter of a second or two, and was mounting a counter-attack.

Sam reared back, side-stepping the First Mate's blade, and backing away across the deck. The first mate backed him further and further towards the opposite side of the ship, as their fighting increased in speed and intensity. Sam knew he couldn't afford to be distracted, as the waves continued to crash around them, and he deflected yet another attack, but … He had to see that Dean was okay. He had to look out for his brother.

He caught just a glimpse of Dean: he was still fighting the commodore and – really surprisingly –losing. Other members of the Celestial's crew had joined in, though: his brother was fending off three or four men, now.

But that was all he saw, before he saw a blade coming towards him, and had to duck, blindly striking out with his own sword and hitting something solid.

The First Mate let out the first indication that he wasn't a mute: he hissed, as Sam got in a horizontal wound to his upper left arm, ripping his fancy tan naval coat. His eyes narrowed in fury and, rather than be perturbed by the injury, he was spurred on: the ferocity of his attacks increased, as his finesse began to fall away in place of savagery that Sam had barely seen in pirates, let alone officers of his majesty's royal navy …

"Sammy!" Cried a desperate voice from the other side of the deck, strangled over the sound of the waves. Sam knew what had happened before he looked over, his jaw slack with surprise as he saw Dean sprawled on the floor, face-down, his sword skittering away from him as Zachariah's boot pressed his neck down to the floor. Three other officers had either grabbed his limbs, or were simply holding him down. Usually, Dean would had been able to take them – but not in these conditions; not with so many of them, and Sammy fighting someone just stage-left.

"Dean!" Sam screamed, clutching onto the familiar wooden railing at the side of the ship with an intensity brought about by fear for his brother.

It was at that moment that the Celestial's First Mate dealt the fateful blow: he got in close, intent on using his fists to knock Sam out and subdue him for capture. He dealt an incredibly strong blow to Sam's left side which, while he was unbalanced in his state of shock, and due to the savage waves beating the ship, managed to topple him so that, before he knew it, he was plummeting into the black waves – black as the Impala, and fringed with white froth. His last-second reflex was to grab whatever was closest for support.

Unfortunately for him, what was closest was not the railing of the ship, nor its rigging. It was his opponent.

The both of them went tumbling over the side of the vessel, yelling as they landed face-first in the icy cold waters, buffeted immediately about by the storm, the freezing temperatures putting them both into shock. The Caribbean waters were never usually this cold, Sam's memory supplied unhelpfully, as if that would rectify the situation. However, it did nothing to ease his struggles, as the insistent waves pulled him under, filling his mouth with salt water.

Sword still in hand, he began treading water, and calling up to his crew – to Dean – to come and help him. He even had the strength and the presence of mind to sheath his sword, knowing he may need it later, but needing his hands free now.

But no one responded to him. Frantically, he cast his gaze around: he couldn't see the other First Mate over the waves. Maybe they'd pulled him out already?

Would they just leave him to die? Surely they wouldn't-

Thunder rumbled ahead, as a particularly large wave appeared, swallowing him whole: it got in his eyes, his mouth; it got down his throat, choking him, leaving him flailing and gasping for breaths he just couldn't take at that moment.

The sea was too strong for him: he couldn't possibly do anything to help himself now, without someone there to guide him. His vision wavered significantly, as he managed the most meagre of breaths before he was pulled underwater again. He began trying to swim, though he didn't know where he was heading, or why.

Dean was going to hang.

His brother was going to die, and so was he.

Up on deck, the older Winchester brother screamed, demanding that the navy pull his little brother from the murky waters below. One of Zachariah's own crewmen stated that they ought to look for their First Mate.

But the Commodore just smiled, looking Dean in the eye as he said,
"Leave them. We have criminals to hang,"

And there began their lengthy journey back to land, with one Winchester brother and his crew in shackles, and one Winchester brother – and a naval officer – lost at sea.

Warm reds and oranges blossomed behind Sam's eyes before he even knew he was conscious – before he even knew he was still alive, and not in Hell, or the bottom of the ocean (though they were one and the same, for all he'd seen).

He marvelled at the fact he was waking up: he thought for certain that he'd made his way to a watery grave, but … What was beneath him was sand. Warm, grainy sand, beneath and in amongst his fingers, as they twitched involuntarily.

At that moment, his calm, frankly unbelievable act of waking up was interrupted by a sharp pain in his shoulder: a jabbing pain that went on and on. Sam recognised that feeling … A boot, on his shoulder, pressing on his collarbone and hurting.

He opened his eyes, immediately screwing them up so that as little of the abundant sunshine all around him leaked into them. He reached for his sword, only to find the belt that held both it and his pistol gone. He realised that the comforting weight of his emergency satchel was absent, too. He started, opening his eyes properly and staring up at a figure that was made shadowy and dark by the back-lighting the sun was providing.

It was him. The First Mate he'd managed to drag down with him. The one who now had his boot on Sam's shoulder, standing over him with his sword – which he'd somehow managed to hold onto – in his hand, directed at Sam's face.

Sam scowled up at his assailant, moving his hands up beside him.

"Do not move," The officer growled, inching the sword closer to Sam's face. "I was hoping you would not wake up, pirate," He added, disgusted.

Sam sneered back at him. "Likewise,"

The other man's visage of anger didn't shift, even slightly. There was no trace of humour, or compassion, or humility there: he was furious at Sam, clearly.
"You pulled me from your pathetic vessel when you fell. You have doomed us both,"
"I didn't-" Sam began, but the officer's foot dug deeper into his shoulder, making him grunt.
"Refrain from speaking," He ordered Sam.

Sam's expression became doubtful, and he shifted his head to the side, casting his gaze past the officer's boot and towards the rest of the land where they'd ended up. A beach, of course – lined by a variety of tropical trees.

Which meant they were … Well, they could be just about anywhere. Great.

"Guess we're marooned then," Sam observed softly, talking mainly to himself.
"I said don't talk!" The officer spat, drawing Sam's attention. The Winchester snorted.
"We're not gonna talk? At all?" He asked incredulously. "… And you're gonna keep your boot on me this whole time?"
"If I have to. If it will stop you from going anywhere. I would hate to see the hangman denied a pair of boots," The First Mate replied, his eyes narrowing.

Sam sighed. It looked like he was going to have to make his way out of this one the old fashioned way – he just hoped his body was ready for another scrap.

Suddenly, without preamble or warning, he craned his neck to bite the officer's heel. He withdrew it immediately with a yelp, his sword flailing in his surprise, allowing Sam to scramble out from underneath the foot, grab the officer's leg, and wrench on it until he fell unceremoniously to the ground. Sam tackled him onto his back, pinning his wrists with his hands, and his legs with his own legs. The officer struggled, but Sam was used to brawling and wrestling – he doubted this pretty-boy had spent as much time practising hand-to-hand combat as he had, fighting with Dean for hours under their father's instruction, for situations such as this.

The officer's eyes widened, regarding Sam anew, as he realised how the criminal had him pinned. He restarted his struggles, but Sam held him fast, sighing as he read what he could see of the other man's face.
"Don't flatter yourself," He said, thinking that the officer wasn't his type, at all. He wasn't someone who would later sell him out, for one. Sam had a poor history with shacking up with people who would sell him for a shiny object, when given the chance. No – this guy would just sell him out, outright.

And second … Well, he didn't look like he'd be into Sam, anyway. That kind of thing was kind of kind of frowned upon in the navy … That he knew of. Hadn't always stopped him in the past, though.

Plus, there was the fact he fucking hated the guy's guts – and the feeling was mutual.

"I'm only gonna kill you … What's your name?" He asked, realising he didn't even know they guy's name. He remained silent. Sam sighed.
"Come on – your commodore didn't seem that shy," Sam reasoned. The officer looked down, and frowned, finally meeting Sam's eyes again, with a jerk of his wrists that failed to do anything yet again. After a few seconds, he replied: "Castiel,"
"Castiel. How long have I been out?" He demanded.
"A day,"

A day. That meant Dean was already a day's sailing away – even with the naval ship making its way slowly towards the closest naval port, and stopping for supplies, Sam would struggle to catch up before Dean was locked away. He might not even make it for the hanging.

While Sam was distracted, Castiel acted: he wrenched one of his wrists free, socking Sam in the face, making him rear back in pain. Castiel rolled them over, flipping Sam onto his front, and pinning his arm behind him. Castiel smiled contentedly at the futile kicking of the pirate's legs, and the grunt of pain he let slip.

"You should really keep a closer eye on your enemy, boy. They always said you were the slower of the two. The daydreamer – some have even called you insane … Amongst other more superstitious titles," He mused, as Sam continued to struggle. But, with Castiel sitting on his back and his arms pinned by his full weight, there was nothing he could do. Except talk (though he was, admittedly, a little breathless).
"Have you seen any ships go past?" He gasped.
"What's it to you?" Castiel asked disinterestedly.
"I'm trying to get rescued, dumbass. Seen ships, or not?" He persisted.

Castiel's grip on his arms tightened at the insult, twisting them far enough that Sam cried out, his eyes watering. Castiel's face didn't even falter at the noise of pain. It was a while before he answered.

"… None from his Majesty's navy," Castiel admitted quietly.
"Pirate ships, then?" Sam specified. Castiel said nothing. "I'm guessing that's a yes, then," Sam surmised. Suddenly, he found himself flipped over onto his back, with Castiel pinning him once more, with both his body and his eyes.
"I do not owe you any answers, Sam Winchester. You have condemned me. Your touch corrupts – you pulled me overboard, away from my fellow officers and my duty," He hissed.

When Castiel wrenched on Sam's coat, yanking him towards his face, Sam studied the officer's face: fair, yet ageing. He was in his thirties, but had a haunted look in his otherwise impassive eyes that indicated that he had seen some things that had aged him. His stubble wasn't usual for an officer of his rank; he also had a surprising affinity for hand-to-hand combat – more than Sam had been bargaining on, at first.

Sam had always thought that the wigs naval officers wore made them look stupid, but Castiel's black one – strewn as it was with sand, and tarnished – lent him the air of being unhinged, and desperate. Sam was willing to believe that this was true, as Castiel's furious eyes traced his face with a burning intensity Sam knew well was reserved for only lovers and nemeses. He didn't wish to experience that gaze any longer.

Grabbing the wrists of the hands that held him close, Sam pulled them free, and scrambled away from the officer in one motion. He brought himself to his feet, as the officer slowly drew himself to his full height, also: he didn't rival Sam, who knew that, at 6"5, his height was his principle advantage in hostile situations. Many times, bar fights had been broken up by Sam simply asking if there was a problem: his stature and reputation encouraged would-be attackers to quit while they were ahead.

However, those things wouldn't cut it this time.

He began to circle, as Castiel did, too: luckily, Sam spotted that he was near Castiel's sword, and made a grab for it. Taking it up, he held it up to the officer, and reasoned:
"Your fellow officers … They didn't even try and rescue you. They easily could have, unlike my crew, who you were going to kill," Sam pointed out, his voice low and venomous.
"Your crew are criminals. Murderers, and thieves," Castiel justified.
"And yours aren't?" Sam asked. Castiel didn't respond to that – though he himself would never take from a ship they were inspecting or had boarded at sea, and had never murdered anyone in cold blood (though he was seriously considering it right about now), he knew that some of his fellow officers had done so.

There was a long pause, where Castiel didn't say anything in his crew's defence – this spoke volumes to Sam, who, having seen Castiel's crew, could say he didn't consider them to be honourable or loyal men. At least, not to their fellow sailors.

"I don't know why you hate me so much – me and my brother are doing you a favour. The people we kill, that our crew stop, are all bad people," Sam pointed out, changing his tone of voice to a more level one. It was time to put the physical fighting to the side, and get down to business.
"Some were officers of His Majesty's-" Castiel began.
"Doesn't mean they were good people," Sam interrupted, his logic irrefutable, even to Castiel.
"What is the point of this taunting?" Castiel asked curiously, with an edge of annoyance to his voice.
"Where are my effects?" Sam quizzed him.
"Why should you care? You have, in your hand, a sword worth ten times the sum of all your worldly belongings,"
"They're important to me," Sam replied, his voice momentarily softer. Castiel knew that, while pirates where no strangers to lies and deceit, what had come out of the younger Winchester's mouth at that moment was a pure truth. However, this moment of softness was soon gone, before Sam raised Castiel's sword: "I won't ask again,"

"The treeline. I hid them in a tree," Castiel confessed. Sam frowned, making a confused expression before shaking it off.
"So – will you be killing me now?" Castiel asked, a little flippantly.
"Well, that depends – do you want me to?" He asked.

Castiel made eye contact with the pirate at that. Sam quirked an eyebrow, his expression still fraught with loathing, but his intentions clear as he finished: "I was intending to make a deal with you, Castiel,"
"Is that so, boy?" Castiel replied, a bitter smile on his face.
"I'll get you off this island … I'll even get you back to your precious naval base, with all your navy buddies – if you help me free Dean," He offered earnestly.
"No. I cannot free a prisoner … I should not even be speaking with you, let alone fraternising with a-"
"Yeah, yeah – I'm a pirate. I know that. But I'm also loyal, to my brother, and my crew. Wouldn't you do the same to help your family? Your crew?" Sam knew that most of Castiel's crew wouldn't hesitate sell Castiel out for their own personal gain when push came to shove – but that didn't mean the First Mate would do the same to them.

He seemed an honourable man, at least: after all, if he wasn't, Sam would be dead.

Castiel was silent for a very long time, looking Sam up and down, and breathing deeply. Sam held his gaze, and his nerve: this was a man who would sell him out at any moment, given the chance – and, honestly, he would sell Castiel out to his fellow pirates without much convincing, too.

But they needed to get off this island.

"Those pirate ships will never take you on board if you don't have me. I could vouch for you … And you could help me break Dean out when we get to the naval port. That's all I'm asking. It's a fair trade," Sam continued.
"Hardly," Castiel snorted condescendingly.
"Hey – listen to me. The captains of those ships you saw going past this past day? They would kill you on sight – they don't take people they don't know, especially ones who look like you," Castiel opened his mouth to intervene, but Sam shifted the sword in his hand, raising it slightly, and cutting off the officer's protests. "So, you can either accept my offer, and fucking stick to it … Or you can stay on this island, while I get away, and try and free Dean without your help,"

The ultimatum hung heavy in the air, as the ocean breeze tousled at Sam's hair and Castiel's regal coat alike.

Castiel remained silent, his fists clenching and unclenching at his sides, obviously not wanting to accept that Sam was right – but he was. No other vessel was coming by any time soon, and he needed to get back to his crew.

"Do we have a deal?" Sam asked levelly at last. Castiel took a tentative step forwards, his eyes still narrowed, as if he were trying to work Sam out.
"You are not quite as barbaric as they say you are, Sam Winchester," Sam cocked his head to the side, as the officer continued: "… But you are a pirate, and I cannot ever trust you,"
"Likewise," Sam repeated his statement from earlier.

Castiel held out his hand. Cautiously, Sam lowered Castiel's sword, and moved to clasp Castiel's hand in his own. As he did so, Castiel drew him in closer, so that they were toe-to-toe.
"But let this be known to you, boy … If you try and betray me, it shall be your last act,"

Sam smirked, nodding with an expression of strong dislike on his face, as he grudgingly accepted the deal he'd crafted, that he was already questioning.
"As long as you get Dean out, I couldn't care less," Sam whispered to him. For a moment, their hands were clasped together: there was no sound aside from those of the ocean, the swaying trees, and the occasional bird.

Castiel's other hand came to rest on top of Sam's, as he continued:
"They call you the boy with the demon blood, you know," Castiel informed Sam. "They say you are part-demon, if such a thing exists," Castiel's voice sounded in equal measures ponderous and disgusted. The officer's hands weren't as soft as expected, but were still soft all the same: much more so than Sam's calloused palms, rough from tugging on ropes, manual labour, and the occasional makeshift-surgery. "… I wonder why they say that,"

"You shouldn't believe everything you hear, Cas," Sam retorted.
"Do not call me that, Sam Winchester," Castiel bristled.
"Then don't call me boy with the demon blood," Sam replied with a superficial smile, before pulling his hand free, and making his way towards the tree line. "Now, which tree did you put my stuff in?"