As you have to know by now, long before Marvel started making movies on their own, they sold the theatrical rights of their most popular characters to other studios. Fox still owns the X-Men, Deadpool, and Fantastic Four. Universal still owns the distribution rights to any solo Hulk movies. And, of course, Sony owns the theatrical rights to Marvel’s most popular character, Spider-Man.

(Honestly, going through all that every time is starting to feel like telling Spider-Man’s origin story again. Yeah, yeah, yeah … people get it. Get to the point.)

Anyway, after two disappointing films – the first and second The Amazing Spider-Man movies – Sony and Marvel entered a back-and-forth negotiation that finally resulted in an agreement to let Spider-Man enter the Marvel Cinematic Universe. And this is why Spider-Man makes an appearance in Captain America: Civil War. (An appearance that was a bit longer than I imagined it would be. More on that when our full review hits on Wednesday.)

But, this did make things difficult for Captain America: Civil War writers Christopher Markus and Stephen McFeely, who were tapped with writing a movie that already had multiple intersecting characters, but they also knew they might have to make room for one more.

“It was, ‘By the way, this could happen and come up with some contingencies,’” remembers McFeely.

Markus adds, “And then it was back and forth. He was in, then he was out.”

So Markus and McFeely had to work on their script without knowing if Spider-Man was in this movie or not. But, as McFeely admits, “We always had ways to do it. And we could have done it without him if it was necessary.”

And when did they find out for sure? “It was only definitively quite late in the process,” says Markus.

McFeely adds, “That recruitment section allows for sort of an easy flexibility.”

Marvel is eschewing the traditional Spider-Man origin story because we’ve already seen that story told cinematically twice before in the last 14 years. When we meet Peter Parker (now played by Tom Holland) in Captain America: Civil War, he already has his powers. But this created a challenge: How do you introduce a character that audiences already love, but are kind of tired of being “introduced” to?