Cas wakes to find that the other side of the bed is empty. He runs his hand across the sheets where Dean had slept, and they were cool to the touch. Dean must have left quite a while ago. He slumps back into the bed, burrowing his face into the pillow. It's a struggle to tamp down the little voice in the back of his mind that whispers He slipped between your fingers while you slept, he's changed his mind and he'll never let you in again. No. It's not possible. They've come too far for that. There were plenty of reasonable explanations for Dean's absence.
His limbs are still heavy from slumber, but he heaves his legs over the edge of the bed and sits up. As he's rubbing his eyes with his knuckles, he hears faint voices drifting down the hall. A breath of relief stutters between his lips. Dean is with Sam. They must have gotten an early start on their research. Cas rifles through the dresser drawers and finds some of Dean's clothes that will fit him. The smell like whiskey, leather and spice. There's also just the faintest hint of smoke that lingers despite all the times the garments have been laundered. His hunter had spent a lot of time burning bodies.
The trace of smoke causes his heart to swell and split in unison. That smell is a reminder of all the monsters his beloved has had to face down in his young life, and of all the people he's lost along the way. It's also a reminder of what makes Dean who he his. He wishes he could undo every injury, every moment of fear, and every goodbye. At the same time he realizes that every thing Dean has been through has formed him into the beautifully damaged creature that he is. The broken angel and his broken hunter. Their shattered fragments fit together like the pieces of a puzzle. Together they were not two crippled beasts, but one powerful force of light and love.
Cas's musings are disrupted by the sound of those voices down the hall gaining volume. He still can't make out what they're saying but it seems that the boys are arguing now. He slides his feet into a pair of slippers and makes his way to them as swiftly as he can with out actually running down the hall. He slows to a stop just out of view from the common room, from which the voices seem to be coming.
"Sam, we're running out of options here!"
"You don't think I know that? But this isn't a good plan! I thought we agreed to stop doing stupid shit to save each other."
"I said I wouldn't doing anything stupid to save you I never said I wouldn't risk everything for him."
"We both know god damn well that he would NOT be okay with this!"
"That's why we need to get started now, and we can tell him when it's done."
Cas walks around the corner into their line of sight. "Tell me what, exactly?"
"Good fuckin job, Sam." Dean mutters as he throws his arms in the air. He immediately turns and stamps down the hall away from them. Cas levels a searing glare on Sam and waits impatiently for an explanation.
"He wants to summon every angel and demon we can think of and interrogate them one by one until they reveal the location on your grace."
"What? No. NO!" Cas runs from the room, following Dean's path. He searches every room until he finally finds the man sitting cross legged in the middle of the dungeon floor with his face buried in his hands. He enters the room cautiously, taking slow calculated strides toward Dean's slumped form.
"I can't let you do this Dean. It's too dangerous."
"I have to do something, Cas, I can't let you suffer. I have to help you. There's nothing else left to do!"
Sam had followed Cas, afraid that the lovebirds might get violent in their ensuing argument. It wouldn't be the first time the two had come to blows, but he hopes that's different now. He's leaning on the door frame listening to them, but neither man has noticed his presence.
"Dean, I am not suffering. I know it's taken me a while to get used to my humanity, but I've never been happier. I have you here to teach me, to comfort me. I couldn't ask for more than that."
Cas feels his eyes beginning to sting as the first tear threatens to roll down his cheek. "Dean I… I haven't been entirely honest with you."
Dean finally lifts his head and stares at Cas with a furrowed brow. "What do you mean?"
"I uh… My grace wasn't… My grace wasn't taken from me. And it didn't 'fizzle out' either. I handed it over willingly."
"Why? Why would you do that?"
"Dean." Cas pauses and swipes his hand down his face. "Dean, I was approached by one of my eldest brothers. He gave me a choice. He told me that I would never be able to truly embrace my feelings of love as long as I was an angel. Angels are capable of loyalty, devotion, adoration and worship. Love however, is a human emotion. He said that it was my decision. I could continue on as things were but I'd never really understand my feelings for you - or I could surrender my grace and live as a human. I handed it over without a second thought."
Dean's jaw was clenched so tight that the muscles were twitching. "Cas, no. You can't do this for me. You've given up too much already. You can't really want to be human, and I'm not worth giving up being a god damn angel!"
"This is WHY I DIDN'T TELL YOU! I knew you wouldn't listen to me! I made this decision after you pushed me away. I knew that even if you never let me in again, that I would rather be able to feel my own unfulfilled desire for you, than to wield the full might of my grace and have my emotions stifled by it."
Sam suddenly feels guilty for listening in, and retreats from the doorway - still without either man realizing he was ever there. He hopes Dean will come around, but he is damn stubborn - especially when it comes to his self loathing.
Cas grips Dean by his chin and forces the man to look him in the eye. "Dean, I have always loved you even when I couldn't possibly understand what that meant. I would do anything for you, and it'd be worth it no matter the cost. But I didn't give up my grace for you. I did this for myself, because it was what I wanted. I haven't regretted my decision for even one second."