A/N: This is totally my headcanon for how Cas is going to come back. THIS NEEDS TO HAPPEN.

Disclaimer: Do not own.

Dean opened his eyes groggily. He looked over at the clock on his right and was surprised to see that it was after 10. He wondered why Sam hadn't woken him up. The other bed was neatly made and none of his bags were there.

Then suddenly it all came flooding back as he felt a warm body press up against his side. He glanced down at the head nestled into his shoulder, and the arm thrown loosely around his waist.

He smiled down at Cas. It was still a bit weird to see the angel sleeping. Dean was still adjusting to the whole idea of Cas being mortal.

There were a lot of things to adjust to. Cas being back… Cas sacrificing his angel mojo to get rid of the leviathans… Cas sleeping in his bed…

He gently shook Cas's shoulder to wake him up. Cas blinked, bright blue eyes catching the light. Dean found himself grinning involuntarily as Cas yawned and snuggled closer.

"Morning," he chuckled.

"Mmm," Cas purred, nuzzling closer to Dean.

Dean briefly wondered where Sam was, and if he had even come home the previous night. But then Cas pressed his lips to Dean's collarbone and all thoughts of Sam disappeared. Dean turned into Cas's embrace and caught his lips with his own.

It had taken Cas's death to make Dean realize just how much he loved the angel. Watching cas sink into the reservoir was one of the most painful experiences in his life, next to watching his brother hurl himself into the pit. When he saw Cas's trenchcoat float dejectedly to the surface, the only thing he could think of to do was take it and keep it safe for when Cas came back. Because he was convinced that Cas couldn't possibly be gone forever.

Sam and Bobby had given up hope after about a month. Sam had started making bitchfaces whenever Dean suggested they look for Cas, so Dean had just stopped talking about it.

But he'd never given up on Cas.

They'd gone on fighting the Leviathans, managing to kill one or two here and there, but they were still wreaking havoc all across the country.

Then it had all come to a head in Los Angeles. The Leviathans had started possessing celebrities. Dean had been arrested for attacking Charlie Sheen, who turned out not to be a Leviathan, but just plain old insane. Then Miley Cyrus went on a killing rampage, and it was oddly satisfying to hack her head off.

The Leviathans had thought that they'd succeeded in their plan for world domination by taking over Hollywood, but they'd made the mistake of all being in the same place at the same time.

And that's when Cas had come back, appearing miraculously out of the blue and reopening purgatory. He'd shoved all the Leviathans back inside, using all his power and then sealed the door and collapsed on the ground. Dean's chest had clenched painfully at the thought of losing Cas again and he'd held Cas's seemingly lifeless body close, tears streaming uninhibited down his cheeks.

"Don't do this to be Cas!" he'd cried. "You can't leave me like this, dammit Cas!" He'd pressed his forehead to Cas's. "Cas," he'd whispered fiercely, "I love you, Cas."

And then Cas's eyes had fluttered open and he'd stared up at Dean in confusion.

"Dean?"

"Cas!" Dean choked out, squeezing Cas impossibly tight against his chest.

"Did it work?" Cas asked.

"Yeah, they're all gone, what did you do?"

"I… I became a mortal," Cas looked away.

"So what, you're going to die again?"

"Yes Dean, I'll live a normal human life, and then I'll die. Just like you will."

"Oh Cas," Dean gripped the ex-angel as tight as he possibly could. "I missed you. Life without you… sucks," he finished lamely.

And that was the moment when he realized that loved Castiel and could never bear to spend another moment apart from him. Somehow their lips found their way together and they kissed a furious, passionate kiss filled with all their crazy pent up emotions.

The kiss was very different from the one they were sharing now, which was a lazy, contented embrace. Dean's hand wound its way through Cas's hair and Cas rubbed gentle circles into Dean's shoulder with his thumb. They lay wrapped in each other's arms, and nothing in the world could touch them.