The MCU is no stranger to in-universe memes. After over a decade of interconnected movies, the characters are able to wink at each other with shared knowledge just as much as they're able to wink at the audience. Of these little gags and references shared between Avengers, Black Widow and Hawkeye's mysterious Budapest trip is one that's lingered around, if only because it was never actually clarified what actually happened or why that particular trip became so memorable.

That is, until now. 9 years after that first Budapest shout-out in The Avengers, Black Widow has finally elaborated exactly what the Budapest mission was, what happened, and why it stuck out so much for both Natasha and Clint Barton.