A/N: I am so sorry for the longer than normal update. I really, really struggled with this chapter. I knew where I wanted it to go but found that every time I started writing, it would go in a different direction and it would be absolutely terrible. I must have re-written the first part about four times before I was happy with it. Once I got that right, the rest flowed easily.

Anyway, I am really nervous about it. I hope I've done the story justice.

Also, I know a lot of you are probably confused about the last chapter. Of course, I can't tell you anything yet, but I promise all will be explained eventually, probably in the next couple of chapters.

Thank you to everyone supporting this story. I look forward to hearing from you, I love all your comments.

So, enough rambling, you've waited long enough for this. Enjoy…

Chapter 13

The bunker shook again, longer and heavier than all the others. Furniture snapped and cracked, photos crashed and smashed, books tumbled and thumped, light bulbs exploded and darkness was starting to descend, room by room. The back-up generator was letting out a strange, high-pitched noise that echoed through the corridors.

Dean Winchester barely paid any of this his attention, he barely heard his brother leave the room to investigate the generator. All he could see was Cas, sitting up on the bed, staring at him… alive.

With his heart thumping like a drum, he cautiously moved forwards, terrified that this was all in his imagination, that the love of his life wasn't really here. He froze when Cas swung his legs over the side of the bed, his mouth set in a grim line and his eyes flashed with the angelic power he possessed.

"Dean?" he asked curiously, with the small cock of his head that made Dean's stomach flutter nervously. This was really him, he knew that. But what if this was some cruel joke? What if he gets snatched away again? "We need to move, now."

Cas stood, his trench coat slightly flapping with the movement. Dean gulped and licked his lips. He needed to ask, needed to find out what had happened. None of what was happening outside the bunker, to the bunker, mattered, not yet. "W-what happened to you?"

The power in Cas's eyes disappeared instantly, leaving them soft and full of love. "Later. I promise. Right now we need to move, Dean."

Disappointment ran through him. He didn't want that, he needed to know now. The grief was still too raw, too real. Before Dean could even blink, Cas was pushing past him. Panic replaced the disappointment. He couldn't let him go yet, he couldn't go back to the real world, not without knowing.

Gripping Cas's hand in his, he swung him around. He barely had time to register Cas's eyes opening wide with shock as he crashed their lips together. The angel immediately melted into him, kissing him back just as vigorously, tongues battling together. Dean's head spun at the contact, at the taste and feel of it. This was real, he was real. He was really there with him, alive. He didn't want this moment to ever end as the relief coursed through his veins.

But his brain was starting to catch up. There was a very real threat, coming to destroy his angel, maybe them all. He needed to get his head back in the game, now. He pulled back and pressed his forehead against Cas's, his eyes opening to latch onto blue. "Don't you ever do that to me again. Understand?" His voice held an authoritative note as he whispered the words.

Cas's eyes widened slightly, mouth hanging open. Dean knew, in that moment, that Cas had no idea what had been going on in Dean's head when he was passed out. All the angel could do was nod his acceptance.

Not wasting any more time, he gripped the hand tighter and pulled Cas along with him. He had no idea where he was going. The corridor was almost pitch black, but he didn't slow his pace as he made his way further into the bunker. His first thought was to find Sammy. Once they had found him, they needed to figure out a way to get rid of the creature outside. There was no way he was going to lose the angel again, he was never going to feel that way ever, not if he had anything to say about it.

Only a few minutes later, they literally bumped into Sam rounding a corner, his chest heaving and nostrils flaring, face flushed, fear in his eyes. "The generator isn't working and I can't figure out why." His voice came broken and breathy as he looked from Dean to Cas.

Tightening his hold on Cas, he felt the his own fear swarm his system. The bunker was suppose to be the safest place on earth, nothing should be able to penetrate its wall. Whatever was succeeding at coming through had to be powerful, more powerful than anything else they've ever encountered.

Cas squeezed his hand back, a reassuring gesture that instantly calmed Dean. He was here and alive, whatever came next, they could deal with together.

"Is there a way to destroy this son of a bitch?" he asked Cas, looking him square in the eye. He looked grim under the dim glow of the remaining lights and Dean knew he wasn't going to like the answer.

The bunker shook again, somehow more violent than the last one. It wasn't going to take this creature long to get through. They needed a plan and they needed it now.

"We can't kill it. Not only would it be almost impossible, but its the only thing keeping The Empty organised. If it dies..." He didn't need to say that he didn't know, but everyone knew it would be very bad, catastrophic even. "But there may be a way to send it back there."

That seemed like a good plan. It was obvious now that Cas was going to take the lead on this. "But," Sam asked cautiously, "won't it just escape again?"

Cas sighed. "No, not if we do it properly. There is a sigil that will not only send it back, but when activated, will keep it there permanently."

"Sounds good. But won't it find a way to get around it?" Sam didn't seem as optimistic as Dean, in fact he seemed quite the opposite.

"No. The only way for it to break free is if someone breaks the lock on it."

Sam nodded his acceptance. "What's needed for the sigil? There has to be a catch."

Dean looked from his brother to the angel and felt his heart stop as Cas shifted next to him, his eyes darting anywhere that wasn't the brothers. There was a catch and it wasn't going to be a good one. "We'll deal with that when we get to it. For now, its our only plan."

Dean could get on board with that. Sam nodded again and they both followed Cas back down the corridor towards the library. Dean refused to release Cas. Something bad was coming, something that wasn't like the creatures they had fought before and he wasn't ready to let go yet. This feeling deep in the pit of his stomach made him shiver.

Whatever the catch was, he suspected, Cas was going to pay the price.

-Supernatural – Supernatural – Supernatural – Supernatural

Agitation hummed through its vessel. This isn't going how he had hoped. Too slow.

It could hear murmurs from within this bunkers walls, nothing distinguishable, as it sent out a wave of dark energy towards the next sigil. These symbols were powerful, more so than anything he'd felt before, nothing its powers couldn't handle, though. Raising the vessels arms, he set the power hurtling towards the symbol. Nothing happened for a moment, but then the earth shook, the symbol lit up a sparkling red. It is a strange symbol, one it has never encountered before. Most of these drawings were squiggly lines, triangles, squares and circles. Different patterns. It would almost go as far as saying they were beautiful, especially when lit up the way they are.

This particular pattern is harder than the others, taking more energy than its suppose to take. It doesn't make it waver, or flinch. It continues to push at it, attacking it with an invisible force. It takes too long, longer than it would like. Castiel, the angel, will surely be figuring out a plan of attack. That wouldn't do. If it ever has a chance of destroying the angel and his friends, then now would be the time to enter this strange place.

Eventually, the symbol lets of a blast so strong that it sends its vessel flying through the air, tumbling head over heels as the wind pushes past. It lands hard onto the concrete floor. If it had been human, it would have hurt all over, or perhaps broken a couple of bones, but it wasn't human and a fall like that didn't do much damage.

It stood and watched as the last of the light went out from the symbol. Breathing a sigh of relief, it moved onto the next one. There weren't many left now. Just a few more. But the most powerful one of the lot is yet to come. It knows it has the power to destroy it, but that was before it used so much power on the others. Regret fills it to the brim. It should have done that one first. A silly mistake, a human mistake.

Never mind. It will have to make do. No matter what, it will make it through in one piece and tear that angel apart, and his friends, too, if they cause it any problems.

-Supernatural – Supernatural – Supernatural – Supernatural

The library was still illuminated by the back-up generators, thankfully. It was gloomy and shadows were cast across the floor and the furniture. Books were strewn everywhere, chairs upturned and the lamps toppled over. Dean cast a wary eye across the disaster and wondered how in the hell they were suppose to find what they were looking for in this mess.

Nobody said anything, each casting their eyes across the job at hand. This was going to take too much time, time they didn't have. Shocking him, Cas released his hand, and Dean fought against the urge to chase after him as he made his way across the piles of books. He fisted his hands at his sides and took in a deep breath to calm himself down. He was being needy and he hated it. Never, in all his years of relationships, has he ever felt like this. Maybe it was because he'd thought Cas was dead and that grief was still pulling him down, drowning him. Or maybe it was because there was an imminent threat just up those stairs and behind the metal door. He shook his head, pushing those negative thoughts to the back of his mind. He would deal with this issue later, first they had to survive the night.

Abruptly, Cas stopped, turning on the spot, eyes narrowed in concentration as his brows drew together. Neither Dean nor Sam said anything, not wanting to break whatever chain of thought the angel was on. Clearly, Cas knew what he was doing and in Dean's experience it was always best to leave him to it, unless his lack of patience outweighed his logic.

Slowly, the angel bent down, his tan trench coat tightening across his back, picking up a red leather book from the middle of the pile. When he straightened again, he thumbed through it, flipping the pages. Dean felt his heart thud in his chest as Cas came back towards them at the other end of the library. Stopping at the table, he allowed the book to drop with a loud thud, not helping Dean's heart at all. Immediately, Sam ran to the book and opened it, his eyes bugging at the prospect of research. Dean rolled his eyes. Even when they were probably minutes from attack, his brother still managed to get excited over a little research.

Sam did the same as Cas, thumbing through the pages, until he came to a stop. The book lay open flat as his brother's eyes scanned the page. "Cas?" Sam whispered, looking up to him with something that looked like pure horror.

Dean gulped past the lump in his throat. Sam had found out what the catch was. A big part of him wanted to know what was going on, wanted to know what they would have to sacrifice in order to do the spell. But a bigger part of him didn't want to know, so he stayed quiet.

Cas eyed Sam with deep depression and sighed. "I know."

Sam looked at Dean, the terror still clear as day. Dean took a step towards them, questioning him without words. "A life is needed, Dean."

There was no time to process his words. A loud explosion rang out, vibrating off the walls, ringing through his ears. Metal shards tumbled into the map room, as he placed his hands over his ears. His eyes scanned Sam and he noticed he was doing the same. Cas merely stood and watched, fear etched across his features.

The creatures was here.

The explosion seemed to last for far too long, but in reality it only lasted a few minutes. The smell of burning metal reached Dean's nostrils as he dived for the gun under the table. Logic told him that this gun would be no good against what was coming, but it felt right and safe to be holding a weapon in his sweaty hands. When he looked back up, clocking the trigger, he noticed Sam was also holding a weapon at arms reach, and Cas held his angel blade. All three of them were ready for a fight.

With his heart in his throat and his eyes scanning the entrance to the bunker, the silence was deafening after the explosion. There was no footsteps, no words, nothing. An uneasy feeling trembled through his stomach. Something wasn't right. If it had made it through the warding, then where was it? Why isn't it attacking?

Cas looked over his shoulder at Dean, their eyes locked. And Dean knew. He knew that whatever Cas was planning meant he was going to lose him for good, he could see the 'goodbye' and the 'I love you' written across his face. Dean wanted to scream at him, beg him not to do anything stupid, but just as he opened his mouth, a whistle rang through the bunker, loud and high-pitched, singing a tune that he didn't recognise.

He snapped his head back to the entrance, his body tense, his grip tightening on the gun. Even though he was watching for the threat, he made sure to keep watch over Cas out of the corner of his eye. The words that Sam had spoken just before the explosion echoed through his mind. If Cas was going to try and sacrifice himself, then Dean would make sure he was there to stop him. He was not going to lose him again.

The whistle kept up its tune, but nothing else could be heard. Dean debated with himself. Should he go and investigate? Or should he stay here and wait for that thing to come to them? He looked at his brother, only to discover he was also having the same debate, he could see it in the way he was twitching his arms, shuffling his feet.

In the end, the decision was taken out of both their hands.

One minute, he was pointing a gun towards the map room and the next it was flung from his clutches, hitting the far wall with a clang of metal. Nobody had time to react to this as he was suddenly gripped from behind, an ice-cold hand circling his throat, putting pressure there with its fingertips, almost choking him.

He gasped at the contact and instinct made him squirm. He could feel the panic start to swell within. As a hunter, getting caught like this was bad news. And this creature was more powerful than anything they've come across to date. There wasn't enough time to break free of the hold, for an arm wrapped around his waist, pulling him in tight. He could feel a cold breath, breathing against his ear, sending a shiver down his spine and goosebumps across his skin.

The smell wasn't like anything he'd ever smelt before. It smelt of rotting flesh, fire, dirty water and smelly socks all rolled into one. He fought the urge to gag as it hit his nose. Instead, he closed his eyes and clamped his mouth shut, trying to hold the stench off. When he felt brave enough to open his eyes again, the first thing he noticed was his brother pointing the gun towards them. The sight of it sent a small sliver of hope running through him, but he pushed it away. The gun would be useless. It would probably kill him long before it did any damage to this creature.

He flicked his eyes to the angel and stifled his gasp. Cas was standing with wide, terror-filled eyes, his angel blade now on the table as he held out his hands with a surrendering gesture. He was giving himself up to save him. Dean wouldn't allow that. He wanted to shout at him, to tell him not to do this. But the grip on his neck increased its pressure, making it near impossible to utter a single sound. Dean was sure there were bruises forming at the pressure-points, but he didn't care. All he could think about was the panic twisting around his guts.

A deep, rolling laugh sounded in his ear, making him shiver again. It was the complete opposite of the whistle, which was surprising. The creatures laugh wasn't a victory laugh, it wasn't a humorous laugh. It was more like a 'here we are again' laugh. Cas seemed to have caught on to that as well, frowning, his lips pressed tightly together and head cocked. It was clear to everyone that Dean was the hostage, probably because of his connection with Cas. In that moment, for the first time since they had started a relationship, regret filled him. If he had been strong enough, brave enough, to resist, perhaps they wouldn't be here now. Perhaps there would be no hostage and they would have a fair shot at the creature. But even as he thought it, he pressed the thought back, because no matter what, he will never regret the time they had shared together, whether that be with his death, Cas's or his brothers. He would never take any of it back.

Cas took a step towards them, eyes flaring dangerously as the grip around Dean's neck tightened. He tried to gasp, tried to wiggle away, but the hold on him was unyielding. He tried to imagine what this creature's next move would be, tried to picture it. This thing had one goal and that was to kill Cas. How could he prevent this from happening? How was it going to move forward with its plans while holding Dean hostage? His brain worked furiously, trying to figure out a way out of this, but it came up blank. The pressure increased, forming bruises across his neck, across his ribs. If the hold around his middle got any tighter, he was sure a couple of ribs might snap.

"You want me," Cas said, his voice full of his angelic power, dangerously so. "I'm here. You want to kill me, then let Dean Winchester go and you can have me."

The creature let out another deep laugh, full of humour at these words. Terror flooded Dean at the sound. Cas was trying to give himself over and that in itself was enough to send him into a panic. But there was something else, something that didn't feel quite right. He worked his brain again as he listened to the laugh close to his ear, feeling the cold breath tickle the lobe, the rankness of it almost making him gag again. The creature, the shadow or whatever it was, stopped abruptly, leaning in close to Dean's neck. His heart froze in his chest as he waited to see what his next move would be, what answer he would have for the angel across the room.

Startling him, he felt a cold wet sensation against his skin, sliding its way up from the bottom, all the way to his jaw bone. He knew what it was, knew that it was a wet tongue, tasting him. The why escaped him, though, as a shudder ran the length of his spine, a sickening feeling fell into the pit of his stomach. The tongue was wet, but rough, scaled almost. Dean whooshed out a harsh breath, trying desperately to get himself under control. He was needed to fight this thing, and if he lost his control, gave into the urge to let the vileness of this situation overcome him, he would be of no use to anyone.

"Hmm..." The creature's lips vibrated against his skin. Dean caught sight of Cas who had now narrowed his eyes, his fists clenching at his sides. It was like he was trying to hold back his possessiveness over Dean. Dean could see the fight in him, could see it had taken great strength for him not to attack, to pull Dean away from this revolting thing. If it had been Dean, he would have already given into that fight, causing chaos in its wake. He admired the angel in that moment, his heart thumped again with the relief that Cas was able to hold himself back… for now. Who knew what would happen if Cas had sprung on the Shadow in that moment.

"Castiel, angel of the Lord. I have been waiting for this moment." The Shadow's voice sounded like a snake, raspy and sly, a hiss almost, sending another shiver through Dean. Its lips were still connected to his skin and he wanted nothing more than to pull away from it. He held himself still, somehow, breathing heavily, waiting.

Cas spread his arms wide. "I'm here. Kill me if you must, just leave Dean be."

Dean felt the head snap up and he knew the creature was glaring in Cas's direction. The pressure on his neck decreased slightly and Dean knew what needed to happen. He tried to catch the angel's eye, tried to pass on the message – distract the Shadow enough, get his grip to slacken and Dean might have a chance of breaking free. But Cas kept his steady gaze upon the creature behind him. He looked towards his brother, trying to catch his eyes instead. Their eyes locked and Sam barely nodded his acknowledgement of what Dean was trying to say. The reprieve he felt at this didn't last long.

"I'm not here to simply kill you, Castiel, angel of the Lord." The voice was now mocking, as though he knew a great secret that the angel didn't know.

"If you're not here to kill me, what are you here for?" Cas asked, his voice full of curiosity and confusion as he cocked his head and frowned. Dean almost burst out laughing at the sight, it was so familiar, so Cas, it didn't seem to belong there in that moment.

The grip tightened again on his neck as its head bent once more, sniffing at his skin, inhaling Dean's scent. "I'm here to destroy you," it snarled as it looked up again.

Dean clenched his fists at his sides, just as Cas had done before him. Aggravating this thing wasn't a good idea. They didn't know what it was capable of, didn't know what power it held or how strong it was. The best thing would be for him to stay quiet. But he couldn't hold back his own question that was fighting its way off his tongue. "What's the difference?" he croaked out. He mentally punched himself. He'd meant for it to sound confident, but it came out weak, holding none of his bravado. Thankfully the creature ignored him. Whether that was because he didn't have an answer or whether it was because he didn't see Dean worthy of an answer, he instead addressed Cas.

"I have learnt many things about you. I admit, my first initial goal was to simply kill you and leave, work done. But… now there are better ways to get my revenge on you. You will loathe the day you had awakened me, Castiel, angel of the Lord."

Dean knew where this was leading, knew that this thing wasn't going to just kill Cas, but make him suffer first, make him live with his choices. The best way to do that was through him. A new determination set itself firmly within as the images of what would happen to Cas if he died here and now flew past his vision. Cas would never forgive himself, would never get over it, move on. He would spiral into a fit of despair and nothing would pull him free, nothing except Dean himself. Knowing this made the determination grip harder inside of him. He would never allow Cas to feel the guilt and the shame of what he would assume he had caused, not if he could do something about it.

Closing his eyes, he took in a deep breath, trying to will himself into calmness. He needed to be calm, needed to free his mind of all thoughts and fears, in order to break free of the creatures clutches. There was no way he was going to allow Cas, the love of his life, to feel anything close to what he had felt when he had thought the angel had died, barely an hour ago.

When he opened his eyes again, a new resolve settled over him, locking his green eyes to blue. Cas had noticed the shift in Dean and fear flared behind his eyes. He knew Dean was going to do something stupid, but he also knew that he wasn't going to talk Dean out of it. The best play was to back his play. Cas offered a tilt of his head, an acknowledgement of Dean's stupidity. Glancing at his brother, he could also see the same understanding and fear behind his eyes. He could tell his brother was planning on arguing, opening and closing his mouth like a fish, but no words formed. Dean wondered idly if it was because he didn't want to give anything away, or was it simply because he had no idea how to change his brother's mind? What words could he offer? This was for Cas, this was going to save his lover's life and Sam knew this.

Once more, he closed his eyes, willing the strength to come forward. He could do this, he thought to himself. Opening them again, he noticed Cas had sneakily gotten hold of his angel blade, ready for the inevitable attack.

He caught Cas's eyes. This was it. He would either survive or die by doing this. But it was the only way. This creature wasn't concentrating on its hostage, it had only eyes for Cas. Both the angel and his brother were being watched too closely, which made this Dean's problem. The only way to get an upper hand was for a surprise attack. Dean had no idea what attack he would go with, he couldn't really think of anything that would ensure he would live, something had to be done, though. And soon. His chances of dying was far too much, but he made peace with it fairly quickly. If there was something worth dying for, it was to save Cas's life.

Of course, he would do everything in his power not to die. It was a hard decision really. Either he dies trying to save the angel, or he dies standing there, doing nothing. Either way, Cas would blame himself. However, he would blame himself less if Dean had made the fatal decision. A phrase he hated more than anything came to mind, but it was utterly fitting for this moment, this decision – Pick the lesser of two evils.

And he did.

Cas's eyes blew wide, mouth parting, a shout coming forth. But Dean was already moving, twisting in the Shadows hold, arms coming up as the hand around his throat lost its grip. He punched the thing across the face, barely registering the crunch of knuckles as it made contact. Instead he forced his mind to focus. The Shadow's eyes flared dangerously, annoyed at the sudden turn of events. That's when Dean's knee came up, sinking into the flesh of its stomach. The grip around his waist dropped. He was free. There was no time to revel in the relief of it as a shot of brown came across his vision.

Dean stumbled back, his eyes growing wide as Cas's arm came down in an arc, angle blade pointing down towards the creature. He wanted to yell, wanted to scream, because surely it wouldn't be that easy. He couldn't do anything, though, frozen to the spot as he watched as if in slow motion. An arm shot out grabbing the end of the blade, stopping the stabbing motion.

A pull on his shoulder alerted him to his brother, shouting at him. He couldn't hear anything beyond the grunts and heavy breathing that now lay behind him. Cas was stuck in a battle with a being more powerful than him. He needed to help, needed to save him, to kill this thing.

Then the words of his brother pierced through the fog. Something about a spell, a sigil. It all came back in a rush. That was how they were going to help Cas, by sending the bastard back where it came from and keeping it there.

He nodded his understanding at his brother, and followed him through the bunker to the store room and grabbing all the ingredients that they needed.

The entire time, he cleared his mind, cleared the doubts that swam through him. He managed to push the fear for Cas away, he managed to push his anger and frustration away. The only thing that wouldn't loosen its grip on him was Sam's words. They echoed and bounced, the whole time he went about preparing the spell.

A life is needed, Dean.