Nothing lasts forever, except you and me.
You are my mountain, you are my sea

Love will last forever, between you and me.
You are my mountain, you are my sea

Dean prays to Castiel the first night in Purgatory. Well, the first night he's not running for his life. He doesn't even think twice about it when he does it, either. He's sitting in this little notch in a tree, knees huddled up to his chest, clinging tight to his knife.

It starts out as a plea.

"Where are you Cas?" He whimpers, barely audible, "I need you man. Come back. Please…"

And that's the end of it. Dean's mostly talking to himself, but Castiel still hears it. It practically breaks his heart.

The second time is more deliberate.

"Cas," Dean whispers to himself. He's leaning up against a tree this time, taking in sharp, deep breaths, trying to catch a break between running from a group of vampires and what he thinks is a windigo. "I know you're out there…" He continues, "And I don't know if you can hear me. But I could really use some help here. I don't know how much longer I can keep running…"

And, as if Castiel just answered his prayers, he doesn't have to start running again. He doesn't think anything of it, just assumes that the vampires got bored or the windigo lost his trail. He doesn't hear the angel yelling off in the distance, trying to distract them and succeeding.

He manages to fall asleep that night. It's only for a couple of hours, but it's better than nothing.

After that, it becomes a routine.

Any time Dean has a second to catch his breath or talk, it's to Castiel. Whether it's in between fighting monsters or running from them, or when he's about to fall asleep, he constantly talks to Castiel. Part of him knows that it's probably hopeless, but he shoves that aside. Because after everything Dean has been through – Hell and Heaven and Bobby's death and the apocalypse, among other things – he's always had something to hope for. And regardless of if he admits it or not, Castiel has become that something. Before, it was avenging his mom, or fighting for his dad, or Sam, or saving their friends, or maybe living in a world without monsters… But now it's Castiel.

Or maybe it's always been Castiel.

Once again, he doesn't really like to think about it. Not that he has much time to think about anything, what with running for his life ninety percent of the time.

Things change when he meets Benny. Despite things being rough at first, Benny gives him a little hope, too. Not as much as Castiel does, but it helps. It helps to have something tangible, someone he can talk to, someone he can work with.

He still prays to Castiel every night.

He's sure that Benny can hear it, but he's past the point of caring.

"Cas," Dean whispers to himself one night. He's laying on the ground and it's wet and dirty and uncomfortable, but he can't bring himself to care. Not with how tired he is. When Benny offered to keep watch while Dean slept, he happily agreed. "We're getting out of here. There's a way. And Benny and I are going to find you and we're getting out of here." He looks up to see Benny looking down at him, and as soon as they lock eyes, the vampire walks away a bit, leaving Dean to continue. And Dean respects the hell out of him for it.

"I need you to answer me, Cas," Dean continues, "Just once. Just so I know you're okay. You… You have no idea how much shit I've been through looking for you, you bastard. It's the least you can do. Show me something. Just… let me know you're okay or something. Please?" He's rambling toward the end. He's tired and kind of delirious and that's probably why "I love you," slips out at the end before he passes out. Right?

It's a couple of days later when Dean and Benny catch their lead on Castiel.

There are no words to describe how Dean feels when he sees his angel (as Benny keeps calling him, and Dean kind of likes the sound of it) crouched next to the water. There are no words to describe how Dean feels when he can finally see him – touch him, feel him, talk to him – again.

It takes some convincing, but Castiel leaves the riverbed with them.

He and Dean don't talk much, mostly because Dean has already said what he wanted to say. All of the things he said in all of those prayers that he thought were going unnoticed. Castiel had heard it. All of it. They don't discuss it and it should bother Dean, but he's gotten pretty damn good at not talking about his feelings, so this isn't really any different.

That is, until he falls asleep that night.

Dean's not sure how long he's been out for, but is woken up sometime in the middle of the night by Castiel nudging him softly. He sits up immediately, eyes wide open and hand reaching for his knife, so used to the dangers of purgatory that it's second nature. When it's Castiel's concerned face at the end of his blade and not a shapeshifter or werewolf or some other awful creature though, he lowers his weapon, face softening. "Sorry Cas, I didn't-"

"I know," Castiel replies, cutting him off, "I shouldn't have woken you."

"Why did you wake me?" Dean asks, looking around. Their campsite is clear, a small fire is still dying a few feet away and Benny is nowhere to be seen, probably off patrolling the perimeter. There's no imminent danger. The night is actually kind of… peaceful. As peaceful as things can be in purgatory.

Castiel looks away at that, avoiding Dean's eyes, "You were talking."

"I was what?"

"Talking," Cas repeats, "In your sleep."

"Oh," Dean says, exhaling. Of course, Castiel is still the same. So horribly socially awkward. But the look on his face tells Dean that something isn't right. He looks upset. "What did I say?" He asks.

"You were praying, Dean," Castiel says, looking back up at him. "You were praying to me."

Deans heart sinks at his words. Of course. Of course he was. He had been doing it every single night for what? Eight months now? Of course he was praying. After eight months of doing it – of missing Castiel – it's probably second nature to him. "I'm sorry, Cas…" Dean says, reaching forward for any kind of contact. He feels terrible. He wasn't trying to make Castiel feel bad, but he can tell just by the look on his face that he did. Dean feels awful, because he understands why Cas did what he did. Why he didn't answer. Why he didn't come to him. He was trying to keep him safe.

"No," Cas says, shaking his head, "No, Dean. I'm sorry. I shouldn't have – I should have come to you."

"Don't," Dean says quickly, grabbing onto the closest part of the angel crouching in front of him, which happens to be his hands. It's only then that Dean notices that Castiel isn't wearing his trench coat. Instead, it's draped around Dean's middle like a blanket. Dean's heart lurches at that, too, and he has to swallow the lump in his throat to speak again. "Don't you dare beat yourself up about this," He says, voice steady despite the way his heart is pounding in his chest, "I understand. I know now. And now you're safe, and you're here. And that's all that matters."

Castiel just shakes his head again. "No, it wasn't fair to you, Dean," He argues, "I heard you every night. I heard when you were terrified and lonely and I didn't come to you, and I should have."

"It's okay," Dean insists.

"It's not okay," Castiel says, voice hard, "I did what I could. When you needed my help, I did as much as I could, but I could have done more."

"You did enough," Dean argues back, almost angry now, "You did more than enough. More than anyone else would have done."

"You don't get it!" Castiel yells, then immediately glances around, making sure it didn't attract any unwanted attention. And Dean just stares ahead, eyes fixed on him because he's never seen him yell. Not like that, anyway. "You don't get it," He repeats, quieter, "I'm your angel. I'm supposed to save you. I'm supposed to protect you-"

"You did," Dean chokes out, almost on the verge of tears at the way that Castiel looks. But he can't cry. He won't. Not here. Not now.

"-I left you. Alone. In purgatory," Castiel continues, ignoring Dean's interruption. "What I did to you was not something someone should do to someone they love."

"Love?" Dean breaths out, eyebrows raised. For some reason, the word hits him hard. He loves Castiel. Of course he loves Castiel. He'd do anything for him. He's done everything for him. But he didn't know…

Castiel shakes his head, "And then there's that."

"There's what?" Dean asks, voice small.

"I heard everything you said to me," Castiel repeats, "Everything."

"And…?" Dean asks, not quite getting it.

"You said you love me," Castiel says simply, "I didn't really get that before. Back on Earth, or in Heaven, anyway. The way that humans love eachother. I didn't get it. I didn't understand that feeling. I mean, I loved my brothers, and my father, of course. But I didn't… I didn't know that you felt that way. And I didn't know I did either."

"You what?" Dean asks stupidly, stunned. He had forgotten about the whole 'I love you' thing. At the time, it was nothing. It was the least of his worries. And by the time that Castiel had told him that he heard his prayers, he had forgotten all about it. It's easy to forget those kinds of things, when you're running for your life.

"I love you, Dean," Castiel says, "And I did everything I could for you, but I should have come to you. I should have come the second I heard you say it."

"Don't," Dean says, shaking his head, "You've done enough. And you're here now. So don't try to tell me that you didn't do everything. You did enough."

"You're crying," Castiel says in a far away voice, like humans are still such a mystery to him. Same old Cas.

Dean chuckles at that, "I am." And there goes the whole not crying plan.

"Why?" He asks, cocking his head to the side like a curious animal.

"Because I love you," Dean says, smiling. At that, he surges forward, catching Castiel's face with his hands and pressing their lips together. He stiffens against Dean at first, surprised by the sudden contact, then relaxes into the kiss, sighing out through his nose, hands going to Dean's hips. And Dean can't help but wonder why he hasn't done this before, because it feels… well, perfect. Though Castiel is dirty and smelly, and his beard scratches Dean's face (and Dean probably feels the same way. His lips are dry and chapped and he can't even remember what toothpaste tastes like) it's perfect.

"I love you, Dean," Castiel says again, confident when they pull apart, and the words make Dean's heart soar.

"I missed you, Cas," Dean mutters back. And God, is that the truth.

"I know," Castiel replies.

"Don't leave me again."

"I won't."

Fic title and lyrics at the beginning are from "Mountains (acoustic) by Biffy Clyro. I suggest you go listen to it because it's wonderful.