So this is how it ends. Dean was pinned up against the wall, angel mojo gripping him so he didn't have a spare millimetre to move. There was a hint of déjà vu about the whole situation with Dean trapped and Castiel walking towards him like a predator.
This was different though. This time Dean was really scared.
This wasn't an angry, smitey, frustrated Cas trying to convince Dean not to give up. This wasn't a friend. This was a cold emotionless creature and there was no mistaking his intent. He was going to kill Dean because of a stupid friggin angel tablet and some nameless controlling power.
Dean couldn't look away, those deep blue eyes had always hypnotised and fascinated him, and he could only look back and wait for the inevitable. There was no escape and his old feelings of depression and self hatred came flooding back. He was helpless. Helpless to save the world, helpless to save himself and helpless save a friend. To stop Cas from doing something that would make the regret and guilt he already felt seem like a drop of water in the ocean. Trapped.
Dean knew how that felt and he had to say something, so he started babbling out reassurances as Cas slowly walks towards him.
"It's ok Cas, it's ok if you do it. I always knew it was going to end some goddam stupid way and I'd rather go out on a job than anytime else. It's not your fault. You have done so much for us and I figure I owe you one. It's not your fault. Just…"
Cas is close now, one step away from him, breathing in his face. His angel blade shoots out from his trench coat and into his hand and he tilts his head to one side. Dean swallows, still not able to look away.
"Please Cas, just get on with it already".
Suddenly Cas drops his head, his free hand supporting himself against the wall behind Dean and his breath coming in ragged gasps.
A tiny rebellious spark lights up in Dean and a thought crosses his mind, maybe Cas can fight this, maybe this doesn't have to be the end, maybe... He remembers Sam telling him about lights at the end of tunnels and a small shred of hope makes him want to give it a go. Maybe this time he hasn't quite given up yet.
"Cas look at me,"
Cas lifts his head slowly and the expression on his face almost breaks Dean's heart. He looks terrified, confused and torn, and his eyes alternate between pleading and dread. Someone was torturing his angel from the inside out. Cas's hand holding the blade begins to tremble like he is a puppet and his arm is on a string.
"Cas, you fight this, you hear me? Remember team free will? Don't let them make you do anything you don't want. You don't want to do this. You saved me Cas. You have saved me so many times I can't count."
Blood begins to trickle out of Cas's eye and his trembling increases.
"Honestly you are the best thing that ever happened to me. No one else ever fought for us like you have. Nobody gave up so much. You don't deserve this, you can stop it."
For a moment Dean thinks Cas is getting control back as his trembling stops, but then the look in his eyes goes blank and cold again and the arm he was propping himself up with drops back by his side.
"I'll always believe in you," Dean whispers.
Cas is so close, and Dean can't move his limbs and so he does the one last thing he can think of doing. He is going to die in a moment anyway.
He closes his eyes and kisses Cas gently on the lips.
The tension snaps.
Castiel collapses, Dean catching him as he falls to the ground, angel blade falling to the floor, its rattles echoing around the room. Cas feels small and vulnerable in his arms and Dean can hear him sobbing and begins to feel his own tears falling down his face. Cas is still crumpled and broken and he has no idea how to fix it.
And then he hears Cas whisper,
"Thank you Dean".