A Vicious Mirror

The infamous Winter Soldier, now an unofficial part of The Avengers, has been tasked by Tony Stark to bring in an unknown threat. Reports of a strange new batch of super-soldiers has been circulating the criminal underground, and The Avengers want intel before they have another "Civil War" situation on their hands.
Bucky is resigned, expecting a bloody fight between himself and a carbon copy meathead. Instead, he is shocked to learn that the person who has been creating fuss is just... a girl?

(This is an alternate timeline where, after the events of Civil War, the Avengers end up begrudgingly adding Bucky to their team, and although they [mostly Tony] hate to admit it, having someone with that much muscle and fighting experience can be very useful. As they start warming up to him, they give him more solo missions, and use his knowledge of super-soldiers to help in fights as more super-soldiers surface around the world. This is an alternate universe, so not everything will be movie-accurate).