Archangels are absolute

Earth, Sam, and Cas

Sam knows something's wrong, he's not an idiot.

He left Dean alone for fifteen minutes to get the rest of his stuff and pee, next thing he knows the motel room is empty with signs of a struggle and a decent amount of blood. 

Worried sick he searches the town for any other supernatural entities, besides the minor demon they just exorcised. Nothing, everything is completely normal, no sulfur or strange symbols or happenings. 

Dean just vanished. 

All he had to go on was a light from the room before Dean disappeared. So Sam goes back to the bunker to research.

Two weeks go by and nothing, the only thing he could find was a wendigo in Vermont.

He finds Cas at his door, dirt-covered, torn clothing, healing wounds, and this look in his eyes... like a deer that's been cornered by a tiger. He explains that Cas overheard a lesser angle saying that his kin had Dean and are torturing him. 

Trying to get information about Cas, who is having a guilt-ridden breakdown every five or so minutes.

He cries himself to sleep a lot. 

One day they're at Bobby's trying to find where Dean could be, when Sam has a vision, a very very painful vision, of the angles stabbing Dean in the stomach then sewing him back together with glowy strings coming from their hands. The room is glowing unnaturally and it's impossible to tell if the room is the size of a closet or a mansion. 

And that's how Sam and Cas find out that angels are torturing Dean in heaven.

Cas has so many nightmares about what his kin can do, what they very well could be doing to Dean, his Dean.

He doesn't tell Sam that the glowing strings are a form of an angel's grace that is only supposed to be used on demons to get information before killing them. 

He doesn't tell Sam that his siblings, especially Naomi, have several millennia worth of experience torturing different beings and are created to be ruthless in caring out what they believe to be God's will. Sam has an idea, but what Cas knows you can only really comprehend by seeing.

It pains Cas to remember that Sam will see his kin's power soon. 

What if Sam blames Cas? For not coming back, for not saving Dean sooner, for not keeping his brother safe in the first place, for being one of them for his whole life, for maybe not being able to save Dean at all...

What has heaven become? It used to be what humans still think, peaceful, happy, harmonious, or was Cas just brainwashed? He's betrayed his home, his people, he's never been sure of his place in his father's universe but now... he's just so tired and lost and tired of being lost. 

Cas doesn't know what he'll do if he finds out that Dean is... that his kind murdered Dean. 

Scratch that, he knows what he might do, he's just too terrified to think about it.

(hint: https://www.pinterest.com/pin/774971048385131519/ )

They get into heaven, it takes a lot of maneuvering to get Sam up there too, without having to kill him and hope for the best, but they make it work. Bobby is waiting on earth for emergency backup and medical help.

Cas sees Jess momentarily, he recognizes her but doesn't know from where (hint: Sam keeps a picture of them together around the bunker) and she tells him where Dean is. Telling him that Dean tried to escape but failed, but is probably still alive since most angels are getting really frustrated.

Cas finds him, god he finally finds that -what were the words Crowley used? oh right- denim-wrapped nightmare. Dean is beaten up and bloody and stitched together like that one woman from that Halloween movie Dean showed him.

But Dean still smiles up at him weakly and Cas swears his heart skips a beat (is that normal? is it supposed to do that? physical forms are confusing). 

Cas's heart breaks when Dean whispers "I really hope you're real" and passes out, Cas carries him out (why does this have to feel like hell all over?) and signals for Sam to get his dam sacrificing ass back down to earth.