[Editor’s note: The following contains major spoilers for Season 4 of Westworld.]

From show creators Lisa Joy and Jonah Nolan, the fourth season of the HBO series Westworld has jumped seven years forward in time and presents a disorienting new world that continues to lead its audience down a path of questioning anything and everything that presents itself as reality. Everything feels unsettling, as you wonder who’s a host and who’s a human. While some who were human are now hosts, some hosts have become different beings from what they once were, and some have evolved in their abilities, all talking steps toward whatever terrifying goal they’ve set their sights on now.

During this interview with Collider, Aaron Paul (who plays Caleb Nichols, a construction worker and veteran who has been living a peaceful life with his family, before hosts set their sights on him) and executive producer Alison Schapker talked about telling a complicated story, what Paul knew and what he didn’t know when he was going into shooting Season 4, what makes Westworld such an exciting show to work on, the Caleb/Maeve (Thandiwe Newton) dynamic, shooting that gut-wrenching moment, and the high standard that Joy and Nolan have for each script.

Collider: Alison, you’ve previously worked on shows like Alias, Lost and Fringe, which have had a lot of twists, in terms of their storylines, and they’ve relied heavily on mystery and mythology. What did those experiences teach you, and how do you feel that applies to a show like Westworld?

ALISON SCHAPKER: I’m comfortable with a complicated story and a careful, structural construction. Alias was a spy/adventure show, and Fringe was more of a scientific/sci-fi show, and then there’s Lost. Westworld loves genre. Jonah [Nolan] and Lisa [Joy] expect you to come well-versed in the tropes of stories because it’s all about stories, how they define us and how we can upend these cultural stories that we’re telling and retelling. So much of that comes down to genres. So, working on all those shows gave me a real lived-in access to what those stories feel like, in the telling. It was easy to contribute to Westworld, on that front.

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Image via HBO

Aaron, how much did you actually know about this season, going in? Did you have the full arc? Do you get a partial framework? Did you have any idea about what exactly was happening?

AARON PAUL: I got a glimpse of where Caleb was at, present-day. I didn’t get an idea of where the story was heading. I sat down with Alison and Lisa Joy, and they wanted to give me an idea of the present world. I knew that the war was over, seven years post the finale of Season 3. I knew that Caleb was suffering from what had just happened in everyone’s lives. But that was pretty much it. That’s really all I knew. And then, throughout the entire season, I just kept poking and prodding because I was desperate to know what was going on. I’m such a crazy fan of the show and always have been, so I’m very excited for the audience to see what we’ve all been doing.

What’s it like, as an actor, to work on a show like this, where not only do you not have all the pieces of the puzzle, but there can be really major shifts in your character going on, and you have no clue that that’s where things are headed?

PAUL: It’s exhilarating. It really is. It’s so exciting. I can imagine it’s the same in the writers’ room. It’s just so exciting to be a part of these stories. Alison has been a part of constructing these insane stories, and we’re just blessed to try to portray them in as honest of a way as possible. It’s the hardest thing, honestly, that I’ve ever been a part of. This coincided with me having a baby, and then a second child, and also the night shoots. Across the board, it was heavy, but so rewarding.

Alison, it’s been more than two years, since we’ve seen the show and these characters, and things have moved forward seven years. What should fans be bracing themselves for, this season?

SCHAPKER: It’s a good question. The way Lisa and Jonah designed it, Season 1 was inside the park and coming to sentience. And then, Season 2 was the struggle inside the park to get out. And then, Season 3 was the discovery that artificial intelligence is already defining the world in very complicated ways, and humans are not just the oppressors, but they’re also subjugated by the artificial intelligence and how to make sense of that. Caleb and Dolores were so integral in addressing that situation, which is very much the present that we’re living in. So, what fans should expect from Season 4 is, if it didn’t all go away and it didn’t all return to normal, and you couldn’t put that genie back in the bottle, what could be a version of what could happen next, as hosts and humans struggle for dominance? Can each one evolve in any way that allows them to co-exist? Caleb and Maeve are very much getting to peeling back the mystery. They’re good guides, as we try to figure out what is going on with our world, who is in control, and what free will really looks like.

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Image via HBO

I’m all for badass warrior Maeve, and I love the team-up between Maeve and Caleb. Aaron, what do you enjoy most about that dynamic? What has that been like to explore?

PAUL: I’ve had the time of my life. Thandiwe [Newton] is just such a superhero. I love that girl to death. I was bummed that we didn’t really get teamed up at all, last season, but I had the joy of coming to set every single day with another badass, powerful woman, in Evan Rachel Wood. I always say that it’s an embarrassment of riches on this show. When I heard that Thandiwe and I were gonna have a big journey together, after reading these scripts, I was like, “Oh, my God, this is so much fun.” And to be able to finally enter an actual park with her, it was so much fun. It was a ridiculous amount of fun.

Your character has that moment that’s just so gut-wrenching, every time one of the characters has it, when they realize that they are not who they think they are anymore. How did you find out about that moment? What was your reaction to reading that? What was it like to shoot that? Did you finally feel like you’d fully arrived in Westworld?

PAUL: Yeah. All of last season, we never left the park. I thought we were just entering into a future world. That was my theory. I was so shocked, just like any viewer is gonna be. I had no idea that was coming. They definitely made sure to keep that from me. I tend to just read my scripts very slow, with an open bottle of wine next to me. I really take my time with them because I feel so excited to not only be reading them, but to really be a big part of them. And so, when I read it, I remember standing up, script in hand and glass in hand, and being like, “Oh, my God, it’s happening!” It’s wild. To then do it was a whole other beast.

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Image via HBO

Alison, what is it like to know something like that is coming, but not tell the actor that it’s coming, to wait for that moment?

SCHAPKER: I really believe in the radical present. When we’re shooting a show, I’m like, “What is this day asking of me?” It’s delicious to know that turn exists in a season. This season, I really feel like we grounded it, and it’s going to pay off. It made sense not to tell Aaron because we didn’t need Aaron to play that level. Caleb had no access to that level. It was conscious in the sense of hopefully helping his craft. To have the rug pulled out from under you, as an actor, is what happened to Caleb. It felt appropriate to that character’s journey. There are other characters where, if we feel like their performance will benefit from a piece of knowledge, then that’s a different story. It’s about giving the actors the tools they need. We wanted Aaron to fully commit to Caleb’s journey in the present, and then experience being blown back like we are, and I know he appreciates that.

PAUL: Yeah.

SCHAPKER: We just wanted to protect the story. Mostly, when we hold things back, it’s because we’re so in awe of our cast. Jonah and Lisa have a very high standard for where a script needs to be, before the actors get it, just because we wanna make sure that it inspires excitement on their part, and that it’s tight enough and good enough and actor-ready. More than any other show, achieving that bar is an achievement, to go to the cast. Each script has its own bar to meet, but it’s not a given. That is something that Jonah and Lisa personally sign off on, with every script.

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Image via HBO

What was it like to also have that moment of reaction, with the shock of Caleb’s daughter not actually being his daughter and having that moment when her face opens up to all of that machinery? That never gets old, watching that happen.

SCHAPKER: It’s so crazy, I know.

PAUL: Yeah, it’s just unreal. Having a daughter of my own, who is just a little younger than Caleb’s daughter in the show, it was impossible for me not to have my human feelings bleed through. I always try to force myself to believe the situations that are happening within the character, and I just try to be as honest as I possibly can. I don’t like to use any of my own history or journey. But with this, I didn’t have a choice. It just kept poking through. It was very hard, to be honest. Some of these scenes were really hard.

Westworld airs on Sunday nights on HBO and is available to stream at HBO Max.