Little Secrets, Little Bucky

Y/n Rogers was a failed attempt to recreate Captain America. When her brother, Steve, was unfrozen they bonded fast and she joined the avengers when he did. Now they live on a floor of Avengers Tower with Sam Wilson and Bucky Barnes. She and Bucky bonded quickly when the team tracked him down and brought him home. He trusts her with all of his secrets, except one. That all changes one fateful day when she finds him deep in his headspace alone on their floor...