'Avengers: Endgame' Writers Disagree With Directors About How The Film's Timeline Works

Avengers: Endgame is clearly a huge movie – not only in terms of its financial success, but also its plot mechanics. And it turns out those mechanics are so complex that even the people who worked on the movie can't seem to get on the same page about it.

Writers Christopher Markus and Stephen McFeely have worked with directors Anthony and Joe Russo on four Marvel Studios movies thus far, including the two most recent Avengers films, and while that group is typically simpatico, Avengers: Endgame is so complicated that it's drawn a line in the sand, with each pair standing on opposing sides.

Keep reading to find out what they disagree about, but warning: there are major spoilers ahead.

Once you introduce time travel into a movie, it opens up a whole host of questions, and sometimes the answers are more complicated than they appear. Case in point: Markus and McFeely disagree with the Russo Brothers about how the film's time travel works – specifically, about what happens with Chris Evans' Old Captain America at the end of the movie.

In a conversation with Fandango, the interviewer asked the screenwriters if the film's ending means that old Captain America was just hanging out while another Captain America was saving the day, and here's how Markus responded:

"That is our theory. We are not experts on time travel, but the Ancient One specifically states that when you take an Infinity Stone out of a timeline it creates a new timeline. So Steve going back and just being there would not create a new timeline. So I reject the 'Steve is in an alternate reality' theory.

I do believe that there is simply a period in world history from about '48 to now where there are two Steve Rogers. And anyway, for a large chunk of that one of them is frozen in ice. So it's not like they'd be running into each other."

That "alternate reality" theory he mentioned? That's the one the Russos buy into. During a recent Q&A, they explained that in their minds, there were also two Captain Americas in the same universe...but there's an important difference:

"For example, the old Cap at the end movie, he lived his married life in a different universe from the main one. He had to make another jump back to the main universe at the end to give the shield to Sam."

You'd think this would be something they all hammered out during their story sessions, but perhaps it points to a flaw in the storytelling. If even the people who spent months making the damn movie can't agree on how it works, how are the rest of us supposed to parse it? Still, it's impossible to deny that the end result of Cap's story arc is emotionally resonant, even if we all still don't quite understand the mechanics that got him there.