Uh - you've been kidnapped to be a Space Avenger. Like the Starjammers, but actually useful.

[ Man, the Time Trapper just has their universe and its analogues on speed dial. ]

I see other people have handled the whole "Cap's here bit. He's also from the past - although not all the way to the Cap-and-his-pal-Bucky-punch-Nazis era. Speaking of, how removed are you from that?