Bucky Barnes was brought back from his supposed death to be a brainwashed assassin called the Winter Soldier. Reformed by his friends, he now fights alongside the Avengers.
A brave soldier, Barnes fights valiantly, but eventually literally falls in battle. Unfortunately, it is the evil Arnim Zola who recovers him, erases his memory and turns him into a highly-trained, but mindless assassin called the Winter Soldier.
The grave course of events set in motion by Thanos that wiped out half the universe and fractured the Avengers ranks compels the remaining Avengers to take one final stand in Marvel Studios' grand conclusion to twenty-two films, "Avengers: Endgame."