"Cas?" Dean whispered, feeling his pulse pick up when he realized the angel had flown off. He gritted his teeth and looked around himself cautiously, seeing foreign shapes he could put no name to creeping towards him through the trees. His hands twitched at his sides.

Then, just as quickly as he had left, Castiel returned, placing a hand on Dean's shoulder and the next thing he realized, Dean found himself in a shallow cave. He whirled around, barely about to make out the lines of the other's face in the darkness.

"I'm sorry, Dean. I thought it best if we're not out in the open for long." Castiel whispered, bowing his head slightly.

Any curses on the edge of Dean's tongue died in his throat. Instead, he let out a heavy sigh and felt around for a safe spot to sit down. "Cas?" He asked after a moment of silence from the angel.

"Yes, Dean?"

Dean stretched his legs out in front of him before drawing them closer to his chest to fight off the bone-chilling cold of the night. "Will it be light soon, or does this place just…stay dark all the time?" He glanced over at Castiel, who was still standing, but not with much of that characteristic stiffness Dean has grown accustomed to.

Cas made a noise in the back of his throat. "I don't know. But," He said, after a beat. "There are some places on the globe where it can stay night for several days at a time. Months even. It gets very cold." He paused, looking towards the mouth of the cave. "Temperatures usually stay below freezing in these areas. Though it can't be lower than forty degrees right now, so I don't think you have anything to worry about here." He chuckled. "Well, besides monsters that even I haven't heard of."

Dean frowned, scrubbing a hand across his face. "Thanks, Cas. That was really helpful." They sat for a few more minutes, only the distant sounds of something lurking in the dark cutting through the quiet of the cave. The calm let Dean's brain catch up with his body's exhaustion, and he fought to stifle a yawn. He felt Cas' eyes on him. "…what?" He muttered.

"You should get some rest, Dean. I'll keep watch." He said calmly, offering Dean a small tilt of his head before he moved closer to the opening and made it a point to melt into the rock, unseen.

"Just don't…fly off anywhere, okay? I don't wanna wake up here al-" Dean paused, grumbling. "With these monsters."

He saw Castiel's silhouette nod. "Of course,"

Dean pressed himself against a rock to block any incoming wind and tucked his hands into his armpits, under his jacket. He wasn't sure if he could manage to fall asleep all folded in on himself, but he'd have to try. No use fighting monsters while running low on juice.

When he woke, he couldn't say how much time had passed, but the darkness hadn't changed, and if he was being honest with himself, he still felt like shit. Worse, even, for having slept on hard rock. He flicked his gaze up to the cave's entrance again, but he couldn't see the dark shape of Castiel lining the edge. A sharp pang of panic pierced his gut and his breath caught in his throat on instinct, silencing his movements.

"Dean," Came the gravelly voice from close beside him, though he could not see the angel it belonged to.

"Cas?" Dean reached out into the darkness, patting the ground. His fingers connected with the edges of the trench coat. Without thinking, he gripped the fabric tight, like a lifeline. "How long was I out?"

Cas shifted, the fabric going a bit more slack in Dean's hand. "An hour or so." He said quietly. "You've trained yourself to nap in spurts when you are someplace you deem unsafe." The light caught his eyes for a second, flashing blue, before bouncing elsewhere. "I've watched you do this before. Wake in a panic, then lull yourself back when you realize you and your brother are safe." Cas' voice seemed to drop, then. Serious with the same sort of sadness Dean felt in his core, mixed around in there with the guilt of not giving Sammy much thought since he got here.

As if sensing his plight, Cas reached out to brush his fingers over Dean's shoulder, drawing them back into the dark gently. "Sam will be fine. He is a capable hunter and he has many friends to call upon for help if he should need it."

Dean grunted a non-committal noise and slid down to rest on his side, back pressed snugly against the rock, his fingers still buried in the tan fabric. If there was enough light, he was sure he'd be able to see his breath in the air. He brought his legs in closer, tucking himself into a ball.

He rested on his free arm and pulled the end of the coat up under his head, falling back asleep within minutes.

The next time he woke, he realized he could feel the body heat coming from the angel, and that he was no longer shivering. "Cas?" His voice sounded thick from sleep.

"Yes, Dean?"

"Did you move closer?" Dean asked softly, not at all complaining if the closeness granted him this comfort. Not like he had anything to prove in this forsaken place.

He heard Cas hum, his voice changing pitch a touch. "Penguins huddle together to conserve heat. They also rest their eggs on their feet so they don't freeze on the ice. Considerate birds, what for being flightless and all." One of his legs shifted and slid out, making a light scuffing sound on the rock. "I remember when I was young I questioned the point of avians that could not take flight, but it seems like we all have our purposes in life, right, Dean?" Cas made a curious noise and sighed. "Go back to sleep. You still need rest."

Dean frowned at the dark before tugging more on the coat and pressing the captured corner against his chest. It didn't cover him any, but what he had in his hand worked better than any blanket ever could.

He slept uninterrupted the rest of the night.