A/N Hello! I wrote this because while I am very much a destiel shipper, I love the friendship between Sam and Cas, and I feel like it gets ignored in a lot of fics. So here is a story that explores Cas and Sam's relationship after the season 8 finale, and then progresses into adorable destiel. Enjoy!

Truth from the Dark

The screams tore Sam from his fitful sleep, and he was on his feet and halfway to the door of his room before his eyes had even opened all of the way. The voice sounded like Cas, but he had never in his life heard his friend scream like that, like his soul was being carved out of his chest with a rusty spoon, and he was terrified about what could possibly be causing it. Could the other fallen angels have found them this quickly? Could they have gotten into the bunker to get their revenge on Castiel?

He yanked open the door to Cas's new bedroom, gun drawn, expecting to see enemies, but a quick glance around told him that he and Cas were the only people in the room. Castiel was still in his bed, drenched in sweat with his blankets twisted around him. As Cas let out another gut-wrenching scream, Sam's sleep deprived brain finally understood. His friend was having a nightmare. Not surprising really, considering all that he had been through.

Sam sat on the edge of the bed, reaching for Cas's shoulder. He could do this without having to worry about bodily injury because Cas, unlike Dean, who lashed out at invisible enemies during his nightmares, was curled in on himself, trembling hard enough to make the bed vibrate, but otherwise immobile.

"Cas!" he said, shaking his friend roughly. "Wake up man, you're having a nightmare."

Cas screamed again, but this time Sam could hear the words in the tortured cry.

"No!" shouted the fallen angel desperately. "No, please! Not them; not him! Not him, please!"

Sam grimaced. He did not want to have to do this, but anything was better than hearing his friend in this kind of torment. Cas let out a whimper that was somehow so much worse than the screaming had been, solidifying Sam's resolve. He delivered a hard slap to Castiel's face, and was rewarded by the sight of blue eyes shooting open. Sam was startled by the rawness and depth of the agony in them.

"It's okay," he said quickly. "It was just a nightmare; you're fine now."

Cas sat up sluggishly, staring at Sam. He reached up to touch the red mark on his cheek, which must still have been stinging. Then, ever so slowly, as if afraid the world would fall apart if he moved too fast, he stretched out a hand and grabbed Sam's shoulder.

"You're alright?" he asked uncertainly.

"Yeah, Cas, I'm fine. I'm right here. Like I said, it was just a nightmare."

"Where's Dean?" asked the fallen angel, looking around in new panic.

"He's fine too, Cas. He took Kevin to check out that potential omen, but he'll be back soon."

Sam was startled when this information caused Cas to break into ragged, wrenching sobs. Sam was at a loss. Castiel had always been Dean's angel, and while Sam loved him like a brother, he had no idea how to bring him comfort in this situation. So he just did the best he could, doing for Cas what would have helped him had their situations been reversed. He settled into a sitting position next to Cas on the bed, wrapping a reassuring arm around his still-trembling friend. And yeah, it was a little awkward, but Cas leaned into the contact, telling Sam that he was on the right track.

"Do you want to talk about it?" the hunter asked.

"Will it help?"

Sam was not sure how to respond to that. He was no stranger to nightmares. He had them so often that it was always a welcome surprise when he made it through a night without them. But he rarely talked about them. If he was honest with himself, it was because he did not want to show his weakness to Dean, or worry him unnecessarily. His older brother had enough on his plate as it was. But Sam did not think that Castiel was weak, and it would be hard to worry about him more than he was already.

"It might," he replied.

The fallen angel was silent for so long that Sam thought he had decided not to answer after all.

"I dreamed…I dreamed that my brothers and sisters had found me here," he began at last. "They were so furious with me. But it was more than that. They were…devastated; fallen and wrecked, and it was my fault. There was pure hate in their eyes, and I deserved all of it."

Sam's heart broke for his friend. He knew what it felt like to let a sibling down, to commit a betrayal so complete and destructive that it felt like he had torn the world down around him. And Cas had done that to not just one sibling, but thousands. But it was not his fault. He had only been trying to do the right thing, to bring peace to the earth by removing the angels from it, and he did not deserve to feel like this.

"Cas, it wasn't-"

"Don't you dare tell me that it wasn't my fault Sam," said Castiel fiercely. "It was my fault. I let Metatron sway me with his lies, let him convince me that it was right to murder an innocent Nephilim and mutilate a Cupid by cutting off her bow. I didn't listen to Dean when he told me to wait. This is on me, Sam, and I know it. But that wasn't the nightmare; I always feel this way."

"Then what?" asked Sam, recognizing that he was going to have no luck trying to assuage Castiel's guilt.

"It was what my brethren did to exact vengeance on me," whispered the fallen angel, the memory of the terror and dread creeping into his voice.

"Did they hurt you?"

"No. I wish they had. I wish that my worst nightmare were being ripped into a thousand pieces, until there's nothing left. But it isn't, and that's not what they did."

Castiel was silent for another long moment, pushing himself more firmly into Sam's side, as if to reassure himself that his friend was still there, that the rise and fall of his chest was still steady.

"They knew that the best way to hurt me, the only way now really, was through you and Dean."

Suddenly, the shouts from earlier made sense. The fallen angel had been pleading with his brothers and sisters, begging them not to hurt the Winchesters.

"Three of them held me, while the rest of them went after the two of you. You fought; you both fought so hard to protect each other, to protect me, but there were too many of them. They took you first, Sam. They pulled you apart, and they made Dean and me watch. The way you were screaming, the way Dean was screaming when you died…"

Castiel shuddered even more violently. Sam squeezed his shoulder tightly, trying to remind the fallen angel that he was there, and very much not dead. He was stunned by the idea that a nightmare about his death would affect Cas so much. Sure, he knew that his friend cared about him, but the man rarely showed his emotions, and now that he was, they were surprising in their depth.

"Dean was so devastated by your death that he barely even noticed when they started on him," continued Cas. Suddenly, Sam did not want to hear anymore. This was Castiel's nightmare, and he could only imagine what could have happened to Dean in it. But the fallen angel was on a roll now, the words pouring from him in a trembling rush.

"The angels pinned him to the ground. One of them shoved her hand into his chest, grabbing his, his heart. But Sam, she did it so slowly. The way he sounded…I-"

The fallen angel broke off, fresh sobs wracking his body.

"Shhh, it's okay Cas," whispered Sam.

He was fighting back tears of his own. He knew what it felt like to watch Dean being torn apart, powerless to stop it. Even after all that he had been through, after hell and the leviathans and the trials, that was still the worst memory of his life. Funny how Cas's worst nightmare so closely mirrored his own.

"Dean's fine," Sam continued. "He'll be back soon."

Of all the nights for Dean to be away. If his older brother did not get his act together and resolve things with Cas, Sam was going to slap him.

"They handed me his heart, Sam," said Cas. Sam flinched. He had thought the nightmare was over, but apparently is had gotten worse. Why had he taken so long to wake Cas up? "They said it had always belonged to me, so it was only right that I take it."

Sam glanced down at his friend in surprise. He usually felt like he was the only one who could see how in love Dean and Cas were with each other, but apparently even the angel's subconscious was tired of waiting for them to admit it.

"Well, they were right about that much," he said.

"What?"

"Cas, I've seen how my brother looks at you. Hell, you must have seen it too, because your own subconscious was using it against you."

"What are you talking about?"

Sam shook his head. This had gotten ridiculous.

"Cas, you don't know what Dean was like before he met you, so you can't see how much he's changed. But I can, and let me tell you it's a lot. I've seen him in love before, but it was nothing compared to the way he is around you. And every time he's lost you, it's wrecked him. So just trust me on this. Believe me when I say that my brother feels the same way about you as I know you feel about him."

Cas stared up at him, disbelief and hope warring in his eyes. Sam met his gaze steadily, confident in what he had told him. A tiny smile tugged at the corners of the angel's mouth, chasing some of the remnants of the nightmare away. But the pain and terror were still there.

"Sam?" Cas asked hesitantly. "Will you stay with me until Dean gets back?"

"Of course."

ooooooooooooooooo

Dean was walking through the silent bunker, trying not to wake Sam and Cas as he made his way to his bedroom. But then he paused, noticing that Cas's door was open. He glanced in to check on his friend, and froze when he saw Sam lying on the bed, holding the fallen angel against his chest. Cas's eyes were closed, and he had one hand fisted in Sam's shirt. Dean's heart squeezed and his stomach dropped, and he realized with shock that he was jealous of his little brother. But that was ridiculous; he didn't have romantic feelings for Cas, so why should it matter if Sam did? But the bitter pain would not go away, and Dean was forced to admit that maybe this hurt so much because he really did feel that way about his angel. Why else would this sight cause such an explosion of pain and misery inside him? How could it have taken him this long to see it?

But there was nothing he could do about it now. Apparently Cas had chosen Sam, and Dean had to live with it. But that did not mean he had to like it. Sam was going to be finding some nasty surprises in his shampoo bottle later. Dean wondered is Cas would find his brother so attractive when he was bald.

Dean was about to continue towards his bedroom, plotting his revenge on his brother while the despair twisted in the pit of his stomach. But then Sam looked up, and relief flooded the younger man's face.

"Dean, thank god you're back," he said. "Come here."

"What?" asked Dean, stepping further into the room.

"Cas had a nightmare. He needs you, man."

"But- I mean, I thought-"

Cas's eyes blinked open and locked onto Dean. The expression on his face was so charged with emotion that it knocked the breath out of Dean. Sam slipped out of the bed and walked over to his brother.

"He woke up screaming because he thought the angels killed you," he told Dean. "He hasn't stopped shaking since."

He all but shoved Dean into the bed beside the fallen angel, and headed for the door. Then he paused turning back to the two men.

"I swear, if you two don't admit your feelings for each other, I'm going to have to resort to drastic measures."

He left. Dean turned to Cas awkwardly, not sure of how to begin, but the angel saved him the trouble. He yanked himself as close to Dean as was humanly possible, and pressed his ear to the hunter's chest.

"Uh, Cas, what are you doing?" asked Dean uncertainly. Without even really thinking about it, his arms snaked around Cas's body, holding him in place. He felt the tremors ease under his touch.

"Listening to your heart," the fallen angel replied.

"Why?"

"Because it's still there, and it's mine. Shut up so I can hear it."

Dean smiled and did as he was told. Somehow that was all that needed said anyway. He pressed a kiss into Cas's silky dark hair, and then tucked his head under his chin. He reveled in the sheer rightness of how it felt to finally hold his angel close like this. He let his eyes close, more content than he remembered being in a long time.

When Sam woke up the next morning, he glanced into Cas's room on his way to the kitchen, and beamed. His brother and the fallen angel were both sound asleep, Dean's body curled protectively around Cas's, and both of them looking more blissfully peaceful than Sam had ever seen them.

"About damn time," muttered Sam as he closed their door softly.

A/N Thank you for reading! I hoped you liked this story. I would really appreciate a review to let me know what you think.