Mercenary(Bucky x Steve x Reader)

Y/n was a mercenary if it isn't obvious enough but, that was her past and none of the Avengers are aware of the people she's killed and the danger she's been involved in. Not until the winter soldier...someone she's been hired to kill multiple times walks in as a recruit from the Avengers. He doesn't recognize her...but her skills he's familiar with. What happens when y/n's mask falls off of her and Bucky recognizes her?