Disclaimer

The Avengers get transported to the theater again to watch Black Widow and the life Natasha Romanoff led before joining SHIELD, they also see her finally destroying the Red Room and Dreykov.
Natasha sees people she never thought she'd see again, she doesn't want them to know, she doesn't think they need, Clint knows her past and that's all she needs, someone to comfort her when her demons get to her.

(Set before Avengers: Age of Ultron, Black Widow and Civil War, ship: Clintasha)