Before Steve Rogers, also known as Captain America, went down in the ice he and Peggy Carter dated. Some may say they were in love. Anyway, something came away from that relationship that Steve never got to hear about. Or more like, someone. Cassie Rogers was taken ten years after she was born, she was taken by Hydra. They injected her with their version of the Super Soldier serum along with another, before training her and putting her in one of the Cryo-generators, pulling her in and out to teach her to be as good as the Winter Soldier. One day, a few years before they found Steve Rogers in the ice, SHIELD invaded a HYDRA base and found the girl, bringing her back to their base to inspect and help.