Warning! This article may contain spoilers for Black Widow. Read at your own risk!
The much-anticipated solo film of the belle of the Avengers is here and it finally explains the almost-a-decade-old conversation or some sort of inside joke between Black Widow/Natasha Romanoff and Hawkeye/ Clint Barton in Avengers (2012) about what really happened in Budapest.
What Really Happened in Budapest?
In Avengers (2012), when Earth's Mightiest Heroes were battling the Chitauri Army that Loki brought to New York City, Natasha and Clint had a brief moment where they talked about the event that happened years ago, Nat said what was happening was "just like Budapest all over again," and Clint answered her that they "remember Budapest very differently."
Fast forward to their last mission together in Avengers: Endgame, when the two were in Vormir about to get the soul stone, they referenced Budapest again and they were even laughing about it as if it was one of the fondest memories they had as partners. Finally, in Black Widow, it was explained what really happened there and while the two of them joked about it, it's darker than it seems.
Natasha shared in Black Widow what really happened in Budapest, her final step to becoming a S.H.I.E.L.D. agent. She revealed to Yelena Belova that the mission was to kill the person behind the Red Room, General Dreykov, and that it almost took them bringing down a whole city to do so.
To pull it off, or so they thought, they had to take down a five-story building and their escape wasn't easy at all as they had to hide for ten days before successfully extracting themselves from the place. Natasha found out from Yelena that Dreykov wasn't dead yet and is hiding with the Red Room still fully functional. Yelena even grilled Natasha that she didn't ensure her kill.
At one point in the film, when the Taskmaster was after Natasha and Yelena, Nat took the injured Yelena to one of the hiding places she and Clint went into – above the train tracks in a nearby station where they stayed for two days; there were even some x and o's on the walls.
While it was brief, at least, now, we all know what really happened in Budapest.