"His brain chemistry is going nuts."
Bruce says, closing the door to Bucky's Stark-sponsored hospital room. Bucky is still only half conscious in there and ice-cold and clammy to the touch.
"There's a chemical compound in his cerebral fluids that shouldn't be there, and it's affecting him on a cellular level. I don't recognize the compound, but it's breaking down rapidly and interfering with everything from neural functions to motor skills."
"So…Bucky's been poisoned? But how-"
"No, no, not poisoned." Bruce interrupts, heading him off, "Not recently, anyway. This stuff is ingrained into his neural structure, and appears to have been there for quite some time. That is, in fact... part of the problem. While the compound degrades, it's taking everything else with it. I'd give it a month at most before you start really seeing the damage... I'm sorry, Cap."
Steve stares at him. The room spins and he has to sit down.
"What do you mean 'damage'?"
"Cryofreezing is extremely hard on the body. Your friend's cells were able to recover and repair damage as it happened due to your shared unusual healing capability, but they were permanently impaired and weakened by the repeated freeze and thaw process.
If my theory is right, this compound is something very like the serum that turned you into Captain America. It was allowing him to keep regenerating damaged cells fast enough to prevent the effects from showing, but now that this serum is breaking down… I think it's just going to get worse."
Steve's mouth is suddenly dry cotton and he can barely find his voice behind it.
"You're telling me he's going to die?"
"If he's lucky, it'll be soon. I'm really, really sorry, Steve."