Marching Off to War
Steve Barton was back, though not necessarily to stay.   He'd sat through a very quick doctor's examination which had revealed that he was in generally good health, though perhaps not having been eating as regularly as he should have.  His right arm was entirely gone, as was his right shoulder and a portion of his pectoral muscle and back.  It had all been replaced by cybernetics that seemed slightly ahead of current technology. 

Loosely over his back, he carried a shield that looked like it once belonged to Captain America.  It had.

They'd commandeered a conference room for a quick war council.

"Okay," Steve said, pacing with the need to keep moving.  He looked older by a year or two, maybe more if you counted the stress and shell-shocked look in his eyes.  "When I disappeared, I ended up in a different dimension.  There, the Earth had been conquered by aliens some time in the 50's. Most of the population had been wiped out.  But some survived as slaves or experiments.  But there was a resistance.  I hooked up with them, started teaching them how to really fight back.  Even, kinda put together a rag-tag Avengers.

We were barely holding our ground.  But now, the mothership, with the aliens leaders, is on Earth.  And we have a plan to take them down.  But we needed muscle.  We pieced together just enough technology, with the help of one of those Avengers, to send me back here."

He swallowed.  "This is that Earth's last chance.  I need you to help me."