When J.J. Abrams was looking for a co-screenwriter for what became Star Wars: The Rise of Skywalker, he thought of someone he’d never worked with before: Chris Terrio, who won an Oscar for writing Argo (and went on to work on Batman v Superman and Justice League, but that’s another story). Abrams was a fan of Argo, and also admired a new, as-yet-unproduced political thriller Terrio had recently written. “The muscularity of the writing, the efficiency of the writing, the intelligence of it,” Abrams told Rolling Stone. “You ask a question and then a page later, the script sort of knows what you’re thinking. And there was a wit and a sophistication to his writing that I really responded to.” For a digital-only piece of our Star Wars cover package (which also includes interviews with Adam Driver, Abrams, Lucasfilm president Kathleen Kennedy and Billy Dee Williams), Terrio broke down the creative process behind December 20th’s Star Wars Episode IX: The Rise of Skywalker.

J.J. told me he was really impressed by the level of familiarity you had with Star Wars beyond the films — the books, the cartoons, the comic books. How did that knowledge play into the tasks at hand for this movie?
It’s sort of a multivariable equation, because if you look hard enough, so many directions in which you could take the story have already been done, and done really well, by novelists or comic book writers or [longtime Lucasfilm director/producer] Dave Filoni and his collaborators in TV shows. So you want to find new paths, but you also want to be informed by all these really good ideas that have come before. For example, the Timothy Zahn novels are really great. I think the Aftermath novels [by Chuck Wendig] are really great. There are episodes of Clone Wars or Rebels [which Filoni spearheaded] that are as good as anything I’ve seen. So you sort of take all that in.

But at the same time, you want to keep the spirit of the Flash Gordon adventure serials that the main saga films have. So while there are times you want to go off on a tangent and explore something that is a more obscure, esoteric corner of the galaxy, you also want to stay true to George Lucas’ original idea, which is that the story just has to be shot out of a rocket and keep going, and the characters always have to be in peril, and you want it to be entirely gripping from beginning to end. The hope is that all that expanded universe stuff could be baked into the DNA without derailing us from from the task at hand, which is to have the adventure feel kinetic and urgent and new.

How much of a story for this film did J.J. have before he sat down with you?
There were certain ideas that he had and Larry Kasdan had [when they were working on The Force Awakens], general directions they wanted to bring the characters. I won’t get into plot ideas, but J.J. always has a clear idea of what he wants you to feel. And then our job is to create a story in which those emotions could be evoked. So we started from a blank page, really. We had a document that we called “the boards,” because originally we would write on a dry-erase board, and then it became a Word document. We would just write story ideas on these boards, and eventually the document grew to be, I think it’s 121 pages single-spaced. We just thought of scenarios that would be interesting, worlds that would be interesting, places that the characters could go or different combinations of character, almost like choreographing a dance.

Like, where can these characters come together? If they do come together, what would their interactions be? What new developments can we create politically in the landscape of the galaxy, or historically, or spiritually, when we think about the Force and the Jedi and what is known or not known. So we started in the most pure place. We acted like two kids who came in every day and were like, OK, here’s the thing that I wish I could see in the last Star Wars. Or, here’s a world that could be really interesting. Or, here’s something Rey might be grappling with. And then it was a Darwinian process of what actually makes it to the next meeting. Maybe we’d lose interest in one thing or think we could reiterate something in a better way. And by the end it was sort of turtles on the beach — there were thousands of ideas that were turtles heading to the sea, and then only a few of them made it to the sea, and those are the ones that proved most hardy and most enduring for the film.

When I first talked to J.J. about The Force Awakens, he said that it really helped at that point to have Larry Kasdan there, in part because it kept him from feeling like he was writing fan fiction. As someone who had been a Star Wars fan, how did you get your mind wrapped around the idea that you were writing this story for real?
I’m still getting my mind wrapped around that idea. We had to approach it like we were just chronicling the history of the galaxy, writing about things that really happened. When we would make a story decision, we were fully aware that this now will become canon, and so are we sure that this is the right story decision? Are we sure about it character-wise? Are we sure about it thematically? Does it seem like it gels with George’s original intentions from Episode IV? Does it gel with what we learned in the prequels and what we learned in the sequel trilogy? Every decision was made that way. But of course, at a certain point you just have to trust your gut, and think: Well, this just feels right. This feels like something the character would do. This feels like Star Wars.

And then you hope that there’s enough Star Wars in your DNA that you’re getting it right. Because the story has seeped into all of our lives so deeply that you always have a gauge of what feels like it’s the right thing and what doesn’t. And sometimes you get it wrong, and you recalibrate. Or sometimes, J.J. and I would disagree, and argue about it, and eventually come to a better solution together about where the characters could go or where they shouldn’t go. So it’s highly unscientific. It’s an organized chaos. And we had the voices of people like Larry Kasdan and George in our heads. Larry Kasdan is a hero of mine. Nobody writes better dialogue or characters than Larry Kasdan. I go back to his scripts — and even unused parts of his scripts — for inspiration and say, why did they make this change at this point in The Empire Strikes Back writing process? And sometimes from looking at the engine and how it works, you get some insight. Why was this scene cut from Empire? Oh, because it wasn’t moving the story forward. Why did they decide to go this way instead of that way in Return of the Jedi? Oh, because it kept the focus on Luke and his father. So, from just looking at the way the machine worked, you start to develop more confidence about narrative choices.

Did you get to come along when J.J. met with George Lucas for this film?
I did. And it’s not as though we we had a conference on specific story points. It’s more about really listening to George. It was almost a philosophical discussion about the nature of the Jedi and the nature of the Force, and about what his intentions were when he was originally writing the first episode. It was like sitting down with a with some grand master and just listening to his wisdom. I don’t even know if George knows to what extent we wrote down and conferred about and really tried to understand the spirit of what he said. As far as the specific story goes, who knows if George would agree with it, but I hope that philosophically he’ll feel we understood the spirit of what he was doing.

Did you read Lucas’ unused treatments for these sequels?
[Long pause.] That one I can’t answer. I do try to read everything that I can get my hands on. There are internet sites that have various drafts of the various scripts from the original trilogy. I devoured [one of those sites]. It probably would be embarrassing to look at the number of times that an address in Santa Monica, California, looked at that site. I wanted to gain that insight into the way that George was thinking, or the way that Leigh Brackett was thinking in her first draft of Empire Strikes Back. Those were superinstructive for me.

A lot of the strange, quirky sensibility of Empire is already there in her first draft. That was exciting to see, that she wasn’t afraid to be weird. Of course Star Wars is a bit weird — it’s in a galaxy far away. But Leigh Brackett, having written so much science fiction in her past, took a lot of risks. I didn’t know much about Leigh Brackett until I started this process and started reading as much as I could by her. A lot of people don’t even know that women wrote Star Wars — she had a name that you might not immediately recognize as a woman’s. And when Larry [Kasdan] comes in, a lot of the dialogue becomes the dialogue of Empire as we know it. Larry brings his own humanist sensibilities to it, and his sense of rhythm and dialogue and wit. So many of the scenes are already there in Leigh Brackett’s draft.

It’s no secret that this movie will tell us more about Rey’s past. One of the most interesting things that Rian Johnson did in The Last Jedi was make it clear that the Force belongs to everyone, even in the movie’s final scene with the kid using it to pick up his broom. So how do you add to her background without taking away from a message that was core to the previous film?
I agree, that’s a really interesting thing that Rian did. It’s a democratization of Star Wars, saying that your lineage and your blood doesn’t necessarily determine who you are, and your past doesn’t determine your future. But we took those provocations as ideas that we could grapple with and hopefully expand upon in this film, because I don’t think it’s a dialectic of one or the other, where either you come from nothing or you are born royalty. There’s a lot of ground in between. Even [Kylo] Ren’s terminology isn’t… When he says “You’re no one” — well, what does that mean? Is that how Rey would think about herself? Does Rey even think of these questions? I’m trying not to reveal any story points here! There’s a Gordian knot in my tongue. I think those are really valid ideas that Rian put forth, but any series of films, especially if you have three, is a conversation — which is, as I said early on when I was talking to J.J., thesis, antithesis, and synthesis. If Force Awakens asks the question of who is Rey and where did she come from, and then The Last Jedi answered it with a negative in a certain way, hopefully The Rise of Skywalker will take those two ideas and create a third thing.

How much of J.J.’s answers about Rey were already set when you sat down with him?
Uh, that one I have to dodge a little bit… When it’s redacted, you know it’s the juicy stuff.

You came to this project from Batman v Superman and Justice League. How did those experiences play into your approach on this movie?
I never thought I would work on another franchise film. And in fact when J.J. hired me, he hired me based on a little political thriller, because I was back to doing that, which is really how I started as a writer. And then Star Wars came about. This was a very, very, very different way of working. It was extremely collaborative, and it’s a credit to the producers, I think, that everyone was making the same movie. That’s not always an easy thing with a movie of this size. Sometimes the studio wants to make one movie, and the producer wants to make a different movie, and the director wants to make a different movie, and the writer wants to make a different movie. On this one, I had an experience very much like Argo, where we all were making the same movie. We agonized over every decision within that, but it was a joyous process.

So the astonishment of this is that the process really has been like the process of writing a small film about characters in many ways. Which I know sounds implausible, but actually, the creative circle was quite small. You really had the feeling that we were we were making an independent film, as crazy as that sounds when you think about the scale and the worldwide exposure of this film. You know, it was Rick Carter and Kevin Jenkins on the design side and [visual effects supervisor] Roger Guyett at ILM and [producer] Michelle Rejwan and Kathy [Kennedy] and [costume designer] Michael Kaplan and Neil Scanlon in creatures. That was pretty much the room. So it was a small room of creators getting to just collaborate and challenge each other and argue and have euphoric days and have down days, as with any artistic process. It really reinvigorated me, because I know it’s not easy to make films that are on a large scale. To see people at the level of J.J. and Kathy doing it this way was really inspiring.