Heaven Above
What Dean hated most about purgatory wasn't the fact that he was constantly on the run, being chased down by every monster him and Sam had ever killed and every evil thing that had been banished from earth before him, it wasn't the constant fear or the pain. It was the fact that there weren't any stars. No sun, no clouds, no daybreak, no nightfall, simply never-ending darkness.
There was no day to look forward to, no light that could brighten his path and chase away the monsters. When he would kill one, ten more would come after him.
In the few precious moments he found peace, he would lean back against a tree and look up, but the starry night sky he'd grown accustomed to would never be there. Just a black void staring back at him.
So he would shut his eyes tight and let his mind take him back to a better time. Back to when it was just the apocalypse looming over Team Free Will's head. There were rare nights, then, when him and Sam would be stopped at some sketchy motel and after hours of sleeplessness Dean would walk outside, sit on the hood of baby and just stare at the stars. He would pretend that there was no heaven or hell, no apocalypse, no demons, that he was just a normal guy gazing into space.
Cas would always appear then, always on the hood right next to him close enough to touch. They wouldn't say anything for a while, both would simply lose themselves in the great beauty above.
"I can see them from Heaven as well." Cas would finally say. "But our view is not limited as Earth's is. We see them all. Every star and planet, galaxy and universe that ever was and ever will be."
And then he'd lean in close and point out every star in that sky and tell Dean what they're like. Every red giant and dwarf star, even planets and galaxies just a little too far off to be seen with the naked eye.
"It must be…incredible." Dean would say.
"It is." Cas would respond in his gravelly voice. "But I still prefer being here with you."
Dean would smile at that and lean in closer. Their foreheads would touch, a hand would caress a stubbly cheek, then soft lips would press together.
That's really what kept Dean going. The memories of cold nights spent on the hood of the impala with his angel.
He'd close his eyes tighter and whisper softly.
"Cas, I…I don't know if you're getting these, but I want you to know that I'm coming for you. I don't care if I have to kill every son of a bitch in this damn place, I'll get to you and I'll get us out of here."
He'd take a deep breath.
"I'm going to save you like you saved me."
And then he'd open his eyes. He'd keep struggling, keep fighting, keep killing until Castiel was beside him once more.
They'd see the stars together again. That he was certain of.