You, Bucky and Steve have been best friends since you were practically in diapers, doing everything together, playing, fighting, and eventually joining the army, but then everything takes a turn for the worst and you and Bucky find yourselves at HYDRA's mercy. During your time at HYDRA, something in your body changes, with the help of a serum. Will these new found powers take over your body? Will your friendship with him survive? Will it turn into something more? And in the end, will you be able to overcome every obstacle, for eachother..?
You are one badass assassin. The deadliest one alive. You're also Steve Rogers' long lost younger sister. When Steve and the Avengers find you single handily taking down one of their targets, they invite you to live with them. You only agree because Steve is there and you want to be with your brother. You don't know Bucky is alive until you get to the tower. Bucky's been in love with you since the 40's. He would constantly beg Steve to let him marry you. Steve would refuse. You admit that you wouldn't mind being with Bucky since you've always felt something for him back. The only thing standing in yours and Bucky's way is, well, Steve. So what else can you do besides have a secret relationship and hope Steve doesn't find out.
This takes place after endgame and infinity war, but Thanos never happened and The Avengers are living together.
I do not own any of these characters (besides y/n) and they all belong to marvel.