On the 38th night, Castiel goes to Dean.
He knows it's dangerous; he is being pursued by Leviathan, and he's got a price on his head. Dean is merely a snack in comparison. Castiel is the prize. The further away from Dean he is, the better Dean's chances for survival. And he swore to keep Dean safe when they found themselves in Purgatory and Castiel was whole again.
But the prayers. The prayers hurt him, go straight to his heart. Dean prays to him every night, and Cas knows what that costs Dean. The faith Dean has in him is humbling, and in spite of his better judgement- as always- he goes to Dean.
Dean is sleeping against a tree trunk, not resting so much as in an exhausted stupor. Castiel doesn't say anything. He's reluctant to wake the hunter, and watching him sleep is peaceful. Like old times. Like before he fell, and after, when they were brothers in arms. When they fought the apocalypse together. Before he aspired to be what he wasn't and broke them.
He thinks about their past together. The first moment Castiel laid eyes on him in hell, torturing some poor soul. He'd gone to Dean and put a hand on his soul, and he'd felt so much. Dean's savage, primal joy in inflicting pain, the curiosity to see how far he could go, the disgust with himself, the self-hatred for succumbing, his grief for losing his humanity. And underneath all of it, pulsating like a heartbeat, his love for Sam. That was the reason Castiel was able to get Dean out of the pit reasonable whole. He's had to leave pieces behind and there were after effects Dean would never recover from, but his love for Sam is what saved him in the pit. Alistair had gotten him to come down off the rack, but it would have taken centuries to fully break Dean; Castiel knew beyond a doubt that love was stronger than hatred and pain.
After all, love had caused a devout angel to fall from heaven.
Castiel hears a movement in the forest and moves slightly, scanning the dark. He should not have come. Unfortunately, Dean hears the noise too and his eyes fly open. He looks up in surprise at Cas, his green eyes weary but lighting up with hope when he sees the angel. His hand is already moving for his weapon, his body tensing for an attack, and he is on his feet before he fully realizes that Cas is in front of him.
"Cas." He says, his voice a growl in his throat. "Man, I thought…"
"I heard your prayers, Dean." Cas says. Dean looks at Cas, waits for him to say more. When Cas doesn't, he reaches a cautious hand out to him to make sure he's real.
"I knew you'd come." Dean licks his lips. "I knew you wouldn't leave me here alone." Castiel can't think of anything to say. After a moment, Dean pulls him into a hug, arms going around Castiel's shoulder and waist. Castiel returns the embrace before he can think about it. Their bodies melt towards each other, finding solace in the familiar. Dean makes a hoarse sound in his throat and tightens his grip on Cas. "Cas." He breathes against Castiel's ear, and there is a change in the way he is holding himself against Cas. Somehow he becomes more fluid, warmer. Cas can feel Dean's breath on his ear, becomes agonizingly aware of how close Dean's lips are to his skin. He's sure if he inclines his head just a fraction, he will feel Dean's lips brush against his skin.
"Say something, Cas." Dean says, still breathing in his ear. Castiel closes his eyes and lets his head incline just a fraction, and yes- he feels Dean's lip move against his skin. Castiel thinks he's smiling. Neither of them cares anymore about forbidden or can't; Purgatory is too vast and lonely to care about human inhibitions.
"I cannot stay, Dean." He says finally.
"Yes you can. You can't leave me alone, Cas." Dean says, his voice barely above a whisper. His breath sends chills down Castiel's spine, and he feels Cas shudder. "Please, Cas." And this time the brush of Dean's lips against him is deliberate, determined. It's like an electric charge and Castiel wants to press closer to Dean. He manages to resist, but just barely.
"Stay with me." And that breaks Castiel's crumbling resolve. He presses against Dean and turns his head, catching Dean in a rough kiss. Dean is ready, lips parting easily and head rolling back. Dean's arm slides down from around Castiel's shoulder, pulling him closer. Castiel's hands find themselves at Dean's waist, and then brushing the top of his hips. Dean makes a sound in his throat again and Cas feels the vibration against his own lips, a low, tantalizing sensation. He groans, full of longing. Dean breaks the kiss to catch his breath, looking in Cas's eyes. Dean starts to lean forward, but in that moment Castiel disappears. He tells himself he hears something coming for him, that he cannot put Dean in danger.
He's scared.
Dean calls his name, swears. Castiel, invisible to Dean, reaches out with a trembling hand to touch his forehead. Dean collapses at the base of the tree, in a deep sleep. He'll either forget that Castiel was here, or think he was dreaming; it's the kindest thing Castiel can do. Castiel watches him for a moment longer, and then flies away. It is too dangerous, he cannot stay.
In the distance, he hears the howl of the creatures that hunt him.