The Snow Leopard is the only other compliant experiment that HYDRA made besides the Winter Soldier, but one failed experiment and her appearance was revived so now she was stuck permanently as a fourteen year old girl. So they turned them into the most lethal pair of assassins known. But now both her and the Winter Soldier have been freed of the tentacles of HYDRA, now it's up to them to help each other find the memories they lost and the people they once were.