What I remember about it is:
• longer, at least 40000+ words
• Bucky/OFC or Bucky/reader
• they all live in Avengers tower, not sure if CA:CW took place
• OC is new in tower and she and Bucky are off to a rough start because he accuses her of being Hydra. He then relents that he mistook her for someone else and they become friends and start dating. The OC than has visions of time when Bucky was Winter Soldier, later she travels there really, like she disappears in present time. It becomes clear that she is the person Bucky remembers and he is extatic because those memories are so important to him.
I remember some scenes so vividly, but have been searching for EVER using any keywords that could be used but came up empty handed.
If you guys have can help I would be SO grateful!