Please, for the love of God, tell me someone recognizes this summary.
There are three separate realities, which all manage to converge at once. One of them is the STXI reality, another where Spock and Jim are prisoners-turned-lovers who break out and lead a rebellion, and... I honestly can't remember what kind of storyline the other K/S come from.
The story deals with several characters from universe A, B and C somehow ending up in each others realities. I think it had something to do with a... black hole? Dying star, maybe? Something having to do with radiation, and sending the other characters back to their own realities...? Actually, I'm pretty sure that there was something that had to do with radiation, and when they figure out how to fix it it turns out somebody has to be in a ship and get very close to said radiation. Only the only bodies around who could handle that kind of radiation without dying immediately are the Spock's. The K/S who came from the prisoner/rebel leader reality come to a mutual agreement (through touch telepathy) that their Spock can't go, because... well, they're the leaders of their crazy, crazy people. Maybe Jim accuses or thinks the only reason they don't want Spock to go is because they're lovers and are being selfish.
I think Jim has a bit of a freakout about his Spock going (even though they're still just friends at this point) to the point where he all but forbids it. So Spock reacts by giving Jim a lovely nerve pinch akin to what Wrath of Khan Spock did to McCoy. I actually think the dialogue there was the same - Sorry, Captain, but I have no time to discuss this logically
. Then Spock flies off and Jim wakes up in time to yell at him via radio while Spock sort of dies in the ship.
This fic was long and plotty and had an amazing
backstory to the rebel Spock and Jim. They met in a prison camp, and somehow became friends when Kirk tried to... blow something up, maybe? At one point Jim becomes ill and Spock takes him to a medic who turns out to be Bones, and while recovering they end up platonically sleeping together. At another point, a guard decides to try to take some liberties with Kirk's body while Spock is forced to watch and I think that might be what sets off the rebellion.
Ugh, I summed that up pretty badly. But if anyone can make sense out of that word gumbo up there and sniff out that link then I will love you forever.I am shocked - shocked! - that there is no prison tag here O.O. Oh well, I did the best I could!
EDIT: FOUND, AND AMAZINGLY FAST, BY THE AWESOME jenna_marianne