He's spying for S.H.I.E.L.D. in Russia.
He's being held hostage.
He works for the S.H.I.E.L.D.
He's on a run.
The Winter Soldier.
Sam Wilson, aka Hydra
Sam Wilson, aka Falcon
Sam Wilson, aka Hawkeye
Sam Wilson, aka Winter Soldier
Because Winter Soldier controlled Rogers' mind.
Because he didn't want to hurt anyone anymore.
Because Captain America knew he's too weak to fight Bucky.
Because Winter Soldier, or Bucky Barnes, was Steve's friend.
He rescued him just to keep on fighting.
He saved him and ran away into the woods.
He let Steve Rogers drown.
He failed on saving Steve Rogers and then killed himself.
Age of disasters
Age of monsters
Age of miracles
Age of glory
He visits a Bucky memorial at the Smithsonian Institution.
He comes to S.H.I.E.L.D. secret headquarters and wants to join the team.
He goes to Russia to find out Hydra's secret plans.
He goes to Steve's house to talk to him.