WARNING: Spoilers for s10e14. If you're not caught up, exit now!

"Things fall apart; the center cannot hold"

"Cas…Dean is in trouble," said Sam, his head falling into his hands as his emotions threatened to take over. It had been so hard seeing Dean so scared, yet so brave and strong. Again, Dean had been willing to sacrifice himself for the greater good, and this time Sam couldn't think of a single way to stop him. He knew it was something Dean had to do, but he didn't have to like it.

Standing outside of that barn with Crowley and Castiel had been absolute torture. He could hear the muffled conversation, followed by the grunts and thuds of Dean being beaten and thrown around by Cain. Cas had had to hold him back a few times when Sam had tried to run up the stairs to Dean's aide.

The way Dean had just crumpled, fallen apart while clinging to Sam had ripped him apart. Dean was his big brother, the one he always looked to for strength and courage. No matter what they had faced, Dean was always the strong one. This time, Dean had been strong long enough to take Cain out, and then he fell apart. Sam had held his brother as the man shook uncontrollably, trying to fight back his tears but losing as he panted and keened exhaustedly into Sam's shoulder.

Throughout it all, Dean had managed to keep the darkness at bay, which gave Sam hope. However, the look in Dean's eyes when Sam had asked him if he was ok told a completely different story. Dean had looked utterly terrified and lost. That scared Sam far more than anything else did.

Sam was shaken out of his reverie when Castiel grasped his shoulder from behind, and he looked up at the angel.

"What do you mean? What is it, Sam?"

Sam gulped as he gestured for Cas to take the seat beside him. He glanced around to make sure Dean wasn't coming around any corners. The last thing his brother needed was to hear Sam and Cas talking about how they were worried for him.

"You've known Dean for a while now; have you ever seen him so…defeated? Scared?"

Castiel's brow scrunched as he gave Sam a searching look. He looked both concerned and confused. "I pulled him out of Hell – I know exactly what a defeated Dean Winchester looks like. Nevertheless, Sam, he kept it together! I had no idea what would come out of that barn after he killed Cain, but he was still Dean. He fought the Mark and won."

"But it's still there, and now the only person in existence who knew everything about the Mark is gone. I know Dean isn't telling us everything either. Cain told him something while they were up there, and I have a feeling Dean isn't going to be sharing with the class," Sam commented to the angel. Dean had said that he was going to go down swinging, and that the answer was inside of him, but so was the problem. Sam felt completely helpless; there didn't seem to be any way for him to take some of the burden from his brother.

"I think perhaps he just needed to rest. He could still tell us what Cain said later. We didn't really ask, you know. I wasn't willing to pry when he was so…" Castiel trailed off, as if he couldn't think of an adjective to adequately describe the state Dean had been in when he had come down those stairs.

"Broken?" Sam suggested with a pointed look. He had never seen Dean completely lose his composure like that – never. "I think…I think he's trying to keep whatever Cain said to him from me specifically. Talk to him, Cas. He trusts you probably more than he trusts me – he handed you the Blade, not me."

Castiel shook his head emphatically. "That's not true, Sam. Dean would do anything for you."

Sam nodded with a sad smile that wasn't really a smile at all. "Yeah, he would. Like keeping something from me that Cain said to him to protect me. Trust and loyalty are two different things. Talk to him?"

Castiel sighed as he nodded and stood from the table. "Of course, but I think we should let him rest for now."

Sam stood up and gripped the angel's shoulder, looking him straight in the eyes. This couldn't wait. "No, now – before it's too late."

Castiel's brow scrunched even more, and Sam could tell the angel was concerned not only for Dean, but for him as well. "All right, I'll go talk to him now. We'll figure everything out, Sam. We always do."

Sam gave an honest smile and a short chuckle as he nodded. "You know, Dean said the very same thing to me not long ago. I think you know him better than you think."

Castiel averted his gaze from Sam's, his cheeks burning in an embarrassingly human blush. "I'll go find Dean. You should get some rest yourself."

Sam gave the angel a knowing look before heading towards his room. "Yeah, I will. Call me if you need anything."

~SPN~

There was an almost hesitant knock on his door, which distracted Dean from drying himself off from his shower. He figured it was probably Sam checking up on him, being a worrywart.

"Come in," he called, tossing his wet towel over to the laundry basket in the corner. He had just slid his boxers on when the door creaked open and revealed his visitor to be Cas, not Sam. Good thing he had decided boxers were a good idea after all.

The angel looked worried and nervous as he stood halfway in the doorway, almost as if he wasn't quite sure what to do with himself.

"Hello Dean. I wanted to make sure you were truly all right. Sam is concerned that you may be putting on a brave face for him."

Dean gave an indignant snort as he pulled a t-shirt on over his head and plopped down onto the side of his bed. "Brave face? Cas, I lost my head and cried all over him. But…I'm ok. You know me – I always bounce back," Dean said with a smirk, though even he could tell it was halfhearted, and from the look on Cas' face, it hadn't been very convincing either.

Castiel moved fully into Dean's room, closing the door with a soft snickbehind him. "You're right; I do know you. That means I also know you like to bury everything until it eats you alive. Now I know Cain said something to you up in that barn, and I don't want to pry. If you don't want to tell anyone, I don't want to push you into it, but Sam is worried sick, and scared."

Dean sighed heavily as he buried his head in his hands. He hadn't been able to keep it together, not with this. He had been depending on Sam to hold him up through this, but he should have known how scared Sam would be. Dean was the one who always stood strong. That wasn't to say Sam was weak, but when the person you've looked up to your entire life breaks down, it's bound to scare the shit out of you.

"Damn it, Cas…I don't really want to talk about this. I didn't tell you or Sam for a reason. I'm...I'm not ready, ok? Look, I'll try to tell you both as soon as I can, but I need to time to process everything."

Castiel nodded as he smiled reassuringly at Dean, who felt the tight band of tension around his chest loosen. "I understand, and I told Sam that you probably just needed time to rest, but he insisted I check on you. Besides – I'm worried too, I just didn't want Sam to know, didn't want to feed his own anxiety."

"Thank you. Maybe Sam is right, maybe I am just trying to keep a brave face for him. That's what I've always done, since Sam was six months old. Hard habit to break, I guess," Dean chuckled, though he didn't feel much humor in the situation.

There was a mostly comfortable silence as Dean tried to take comfort from Castiel's presence. It had been a while since he had even seen the angel, who had been doing who knows what looking for Cain. It felt like the only time he ever saw his best friend was in dire emergencies, but that was no different from the rest of Dean's life.

He only wished he had more time to spend with Cas, time not consumed with hunting, fighting angel and demons, fighting for their lives. He still remembered the one time before the apocalypse where he had taken Cas to a strip joint, trying to get the angel to loosen up and lose his virginity, considering they were sure they'd be dead by morning. To this day, that remained one of Dean's greatest memories.

Dean jumped as he felt a hand lightly touch his shoulder and he looked up from his seat on the side of his bed. Cas was standing in front of him, his expression still full of concern. Dean felt his chest ache with who-knew-what kind of emotion. He never could figure out what he was feeling around the angel, and it drove him crazy.

"You don't always have to be the strong one, Dean. It's ok to be frightened, to be upset or worried. I know you want to hide it all from Sam because you want your brother to keep seeing you as some sort of super hero, but you don't have to hide from me. I understand probably better than anyone else does how hard it is to fight the darkness inside of you, to be so frightened of your own potential and feel completely powerless against it. I'm sure Sam can relate, given his experience with demon blood.

"What I'm trying to say is that if you need someone to talk to, someone you don't have to put on a façade for – I'm here."

Dean's emotions seemed to spiral out of his control with every word Cas said, so that by the end of the angel's pronouncement, Dean was shaking with suppressed tears. He never let the chick flick moments affect him so much, but he had fought the Mark for so long, and had kept it together with every last shred of strength he had. There was no strength left in him.

Before he knew it, tears were streaming down his face as he gripped the lapels of Castiel's trench coat and pulled the angel close, wrapping his arms around him as he gasped and shook.

"Cas," Dean croaked through his tears. Maybe he could let go, just this once.

Castiel maneuvered so that he was sitting on the bed beside Dean, and pulled the hunter into a tight embrace. "It's ok, Dean. Let go…I'll watch over you. It'll be ok, you'll see."

It felt so good to have someone just hold him and tell him everything was going to be ok, even if he didn't really believe it. Dean allowed himself to be slowly pulled down onto the bed so that he was laying curled on his side, tucked into Cas' side with his head on the angel's chest. Castiel's arms were still wrapped around him, his hands rubbing circles into Dean's back, bleeding the tension he wore like a shroud right out of him.

"Don't tell Sammy," Dean whispered as his tears began to dry up. He was still shaking with emotion, and didn't have any plans to pull away from the angel any time soon.

Castiel brushed a tear from Dean's cheek as he tilted his chin up so that green eyes met blue. "I won't. Go to sleep; I'll be right here."

There was a moment of hesitation as Dean allowed a traitorous thought of how this would look if Sam were to walk in. He pushed it away, however, and curled up tighter into Cas' side. He sighed in appreciation when the angel snapped his fingers and the blanket they had been lying on top of covered them instead. He smiled tiredly up at his best friend before closing his eyes and finding a comfortable place to rest his head on Castiel's chest.

"Don't leave," said Dean, feeling his stomach clench in anticipation of Castiel's reaction. He wasn't sure what was happening, but this felt like a whole hell of a lot heavier than just friends comforting each other did. He purposely wasn't looking too much into it, lest he psych himself out of the comfort the angel's arms were providing.

Castiel's arms tightened briefly around Dean before the light on the bedside table winked out, plunging them into darkness. "Never."

~SPN~

Sam had tried to go to sleep, but his mind just wouldn't shut off without checking on Dean. He had left his door open and so he had heard Cas enter Dean's room after knocking, but he'd yet to hear him leave. He was sure Cas could handle whatever Dean threw his way, but he needed to see that his brother was all right.

He had been about to knock on Dean's door when he heard muffled voices. Feeling like a complete jerk, but using his worry to justify it, Sam pressed himself closer to the door so that he could hear what his brother and the angel were saying.

"Don't leave."

"Never."

Sam felt his cheeks heat as he quickly moved away from the door, regretting intruding on such a private moment. He had always sensed something between his brother and Castiel, but had always just put it down to their 'profound bond', formed from Castiel raising Dean from Hell. However, if Sam were honest with himself, he knew it was definitely more than that. He had put it out of his mind, as he knew his brother would probably always deny any feelings he had for Cas.

However, Dean had been on edge already, and Castiel had a way of getting things out of people that they wouldn't normally tell anyone else. Maybe Dean was finally allowing himself to feel, allowing someone to help him through his emotions. Sam felt a slight twinge of jealously that Dean had not been willing to lay everything on the table in front on him, but if there was one other person in the world that he trusted with his brother, it was Castiel.

Finding comfort in knowing that Cas would take good care of Dean, Sam headed back to his room, confident he could finally get some rest of his own.

Maybe Dean was in trouble, and they surely had much more Hell to get through before the Mark of Cain would be done with his brother, but for the first time in a long time, Sam saw light at the end of the tunnel.

~Fin~

A/N: The title of this story is one of my all time favorite quotes from my favorite poem by William Yeats called "The Second Coming".