Falcon and Bucky

You're a 19-year-old girl, barely born. Years ago, Hydra kidnapped you and trained you from childhood to be a perfect assassin. That was five years ago, when you were 14 and on a mission for Hydra. The Avengers rescued you. You'd known nothing but Hydra and killing your entire life, and the government was afraid of you because you'd killed almost as many people as Bucky did when he was the Winter Soldier, and he did it in fifty years. But you weren't like that anymore. It still hurts; you have nightmares, and Bucky, who was the Winter Soldier, had them too. So for a while, you helped each other, but then the Blip happened, and he disappeared along with many of the Avengers, and you were left alone. But when they returned, you didn't know anything about any of them until one day you see on the news that there's a new Captain America, not Sam Wilson, Falcon, because Steve had given him the shield. The new one is called John Walker, and days later, the news reports that there's an organization of people trying to return everything to how it was during the... blip, where there was more peace and fewer borders, and while you're in your apartment, Bucky and Sam knock on your door.