• 'Dune: Prophecy' star Jessica Barden filmed one of her most intense scenes at the edge of a real cliff.
• Barden plays the younger version of Valya Harkonnen, leader of the Sisterhood, on the prequel series.
• In episode three, Barden stood in the freezing rain for hours to film her big scenes.

Jessica Barden may play one of the most inscrutable characters on "Dune: Prophecy," but in real life, she's more than happy to share whatever's on her mind. And when it came time to film one of her most intense scenes, that was: Why am I doing this?

Barden plays young Valya Harkonnen, the vengeful and ambitious young woman who becomes the leader of the Sisterhood (a group that would eventually become the superhuman-powered Bene Gesserit by the time of the Denis Villeneuve "Dune" films).

She shares the role with Emily Watson, who plays an older Valya secure in her position of leadership over the group. In the flashbacks that center on Barden, though, Valya is still doggedly climbing that ladder to achieve more power, which, at one point involves standing in the freezing rain for hours.

"It was our second day of filming as well," Barden told Business Insider of the tough scene. "It was also December in Hungary."

The scene in question takes place during "Dune: Prophecy" season one, episode three. It delves into Valya and her sister Tula Harkonnen's backstories, and it's Barden's biggest episode yet. At one point, Valya and the other acolytes are standing out in the rain as a trial.

Barden said that camaraderie was the key to braving the cold during filming. "The crew was amazing. They make a hot tent, and they bring you tea, and a towel, and stuff. And when you're together it's fun, and you're just laughing like, 'Why are we doing this? This is crazy,'" Barden told BI. "But then, when you're by yourself, you're just like, 'Why am I doing this? This is crazy.'"

Once Barden was on her own, she asked episode director Richard J. Lewis not to cut filming short if he felt bad for her standing out in the cold — if she was going to do this, she wanted it to look good. Lewis agreed and even gave her the feedback that she looked "too cold" at some points and needed to tone it down.

"I'd be like, 'I'm going to kill you. I'm literally going to kill this man,'" Barden joked. "But I was really proud of myself when I did it, when it was over."

Later in the episode, Valya experiences the Spice Agony, a potentially fatal rite of passage required of all Reverend Mothers, at the edge of a cliff on the Harkonnens' home planet. Turns out, none of that landscape was CGI — they were filming on location at a real cliff at 5 a.m.

"It was a sheer drop," Barden said. "And my eyes would close, and act in this agony, and Richard would be like, 'Okay. Imagine it's going through your veins.' And the whole time I was like, 'Oh my God. I'm going to fall off the cliff.'"

The "Dune: Prophecy" season finale airs Sunday at 9 p.m. ET on HBO and streams on Max.

• HBO's "Dune: Prophecy" explores the origins of the Bene Gesserit sisterhood.
• The show is loosely based on a "Dune" prequel novel but expands past its scope.
• Showrunner Alison Schapker spoke with BI about bringing the franchise to the small screen.

"Dune: Prophecy" goes way back, thousands of years into the history of the powerful women who shaped the history of the entire "Dune" universe.

"Any 'Dune' fan knows it's just so endlessly deep in its lore, and its worldbuilding, and its specificity," showrunner Alison Schapker told Business Insider. "But for new fans who are coming in, I feel like the best way to discover a world is always through your characters."

The HBO prequel series focuses on the origins of the Bene Gesserit, the shadowy organization responsible for a breeding program meant to bring about a messiah known as the Kwisatz Haderach. In Frank Herbert's original novel and Denis Villeneuve's film adaptations, that messiah is Paul Atreides (played by Timothée Chalamet in the Villeneuve movies), a young man who shapes the history of the Imperium.

"Prophecy" is loosely based on "Sisterhood of Dune," a novel with the same premise co-authored by Herbert's son Brian and Kevin J. Anderson. It follows Valya and Tula Harkonnen, sisters from a then-disgraced family — not the powerhouse the Harkonnens are in Villeneuve's films — who shape the development of the Sisterhood 10,000 years before Paul's birth.

The prequel novel served as a jumping-off point, but the creative team had free rein to build on the story, creating new characters and twists along the way. It was a challenge that Schapker, a sci-fi veteran known for her previous work on "Westworld" and "Altered Carbon," enthusiastically approached.

Schapker spoke with BI about adapting the vastness of "Dune" for the small screen, which involved juggling interpersonal drama, science fiction scope, and multiple timelines to tell the Sisterhood's story.

You were brought onto "Dune: Prophecy" after it had already been in development. How did you approach it?

This was a corner of the "Dune" universe that I really dove into. I was much more familiar with Frank Herbert's vision of "Dune." Over the years I've always been on the lookout for "Dune." But then obviously, Denis' films come along, and I think unlocked it in a new way for fans and new people, and just is so elegant, so immersive, so artistically rich.

I approach every project the same way. I want to look at everything that's there, everything I inherit, and build upon it, and deepen it, and prune it, and just continue the process of crafting story. We're only six episodes — I would say these are very robust, full hours of television, and there's a lot of discovery that goes on as you're doing it, which is really just the best.

This show has to do a lot of exposition for "Dune" in a very short timeframe, especially for newcomers. What was top of mind for you when it came to setting things up in the first episode?

Brian Herbert and Kevin J. Anderson in their novels were not just looking at the origins of the Bene Gesserit, but they put two Harkonnen sisters right in the middle of it all. I felt like that was so exciting as a "Dune" fan, as a writer to explore, "Okay, what does it mean that this organization that's going to have such influence had a Harkonnen shepherding it? What does that tell us about the Harkonnens, and what does that tell us about the sisterhood?"

It was really fun to have this familial sisterhood between Valya Harkonnen and Tula Harkonnen at the center of a larger sisterhood with all the women at the school. That baked-in choice I thought was so strong, and the premise unfolded from there.

Telling the sisters' story requires two different timelines in the show, with younger and older versions of both Valya and Tula. How did you manage that, and craft the throughline of their relationship in both eras?

I feel like we're all a product of our past selves, and our history over time. The Bene Gesserit and the sisterhood, at this time period, they're big on long-term plans, and eventually, they're going to put into motion a plan that would last many thousands of years.

Part of it begins when Valya Harkonnen comes into control of the sisterhood, when she's a young woman played by Jessica Barden. That is very much the time period of the books. So when we were doing a direct adaptation, a lot of that is this younger Valya Harkonnen and her rise to power in the sisterhood.

But we also wanted to have room to create a rich television series, and see an older Valya, played by Emily Watson, a little more in control — where she took the sisterhood, and then how she was tested as part of a larger exploration of how it went from the Sisterhood to the Bene Gesserit. We wanted to look at the organization over time.

That's the new stuff we were extrapolating. We were doing it in conjunction with the Herbert Estate, but it allowed us some room to create and bring in some new events and characters.

In this show, you have that grounded familial relationship, but also the space opera scope of a "Dune" property. How do you balance that?

That is my joy. That's everything I want.

Obviously, we're never going to have an IMAX screen — but I do think "Dune" warrants an epic, but intimate juxtaposition, because it is asking you to think about time and worlds and politics and the impact of things like war, and power, and nature.

I think the epicness really helps those themes come through. It puts you in your place almost as a small piece of something larger. I feel like the humanity of it is woven into this bigger tapestry of the universe, and so I think some of the epicness really helps that feeling.

Early on in the development of this series, there was a push to bring in a female showrunner. I'm curious about how you've reckoned with that side of the discourse, and how any of it plays into this being a show functionally driven by women on the page and behind the camera.

It's incredibly rewarding. First of all, I think we have to start with "Dune" and the fact that women are players in such a pivotal and real way. Right in the narrative, you're brought on board as an equal in terms of who's pulling the strings, and the Imperium. That's just exciting. As a creator, of course I want my women characters to be having an impact on story as much as anyone else.

But yes, there's nothing better than feeling all your characters have a specificity and a voice. It was really fun to center the Bene Gesserit, and the sisterhood, and the Harkonnen sisters.

At the same time, it's certainly not out to be a treatise on gender. I had a lot of discussions with the Herbert estate. Just that idea that he's always thinking about how social structures and social forces might change, but be familiar even while utterly different.

"Dune: Prophecy" airs on Sundays at 9 p.m. ET on HBO and streams on Max.

• Emma Canning plays young Tula Harkonnen in "Dune: Prophecy."
• The third episode dives into the Harkonnen sisters' backstory and the pivotal choices they've made.
• In an interview with BI, Canning broke down the major reveal about Tula's past with the Atreides.

Warning: Major spoilers ahead for "Dune: Prophecy" season 1, episode 3.

After a fatal series premiere, "Dune: Prophecy" has claimed more lives — but rather than burning up from the inside, these victims died quietly.

Episode three, "Sisterhood Above All," dives back into the Harkonnen sisters' childhood. Before they were Reverend Mothers, Valya and Tula grew up on the cold-weather planet Lankiveil when House Harkonnen was scraping by. Their brother, Griffin, is killed, and Valya, who believes Vorian Atreides to be responsible, swears vengeance against the family that engineered the Harkonnen family's fall from grace.

It's not Valya who exacts that price, however. It's her younger sister Tula, played by Emma Canning as a young woman and Olivia Williams as an adult. To carry out her and Valya's revenge, Tula seduces (and falls in love with) Orry Atreides. In turn, she poisons him and almost his entire family on a hunting trip the night that he proposes to her.

Williams broke down the Atreides massacre with Business Insider, including Tula's decision to kill her fiancé — and her choice to let the youngest Atreides live.

Tula seems to be wrestling with how to address Orry after she's already set the Atreides massacre in motion. How did you approach that tension and her motivation after he proposes to her?

In that sequence, from the moment she hands over that bucket of poison at the fire, it really was about having a plan, being faced with an obstacle, and having to change your plan. I think she walks up to the house — he should go down, join them, smear himself with poison, they'll go to bed, and so he'll be with them.

He's had a really tough day, he had to put down the horse, and that wasn't something she predicted. So then it becomes a thing of, "Okay, well, he's not going to leave the hut. What can I do to keep him in the hut? How can I stop him from going outside?"

I think then that's what the game plan becomes. She opens up to him, she says yes to his proposal. All of those things, I think the undercurrent is, "I can't have you leave right now."

As a viewer, there's a sense of resolve but also reluctance on Tula's part. How did you approach those more difficult, almost contradictory emotional beats?

Contradiction is really helpful as an actor. Richard Lewis, our director, and Alison Schapker, our showrunner, had given me this huge contradiction in really being very clear that this is a love story: She's in love with Orry, and she is falling deeper and deeper in love with him. So I have this major pull between my love for family and my loyalty, and then my growing love for him and my growing loyalty to him. So the complexity of the push and pull is line by line.

It really is dependent on how Milo Callaghan, who was playing Orry, would deliver certain lines. We were really lucky in prep that we got to know each other. We had to do horseback riding. We had about two weeks of that, so we were good pals by then, which was really lovely.

We shot this sequence very isolated from the rest of the scenes that I played, so Milo and I kept being like, 'Are we doing a short film with Richard?' It felt so intimate. It felt so small. I think we had to keep reminding ourselves, "No, this is 'Dune.'" But that was really lovely in that it really took the pressure off. They're just really good scenes and really high stakes.

Tula eventually does kill Orry, but she decides to let Albert, Archie Barnes' character, live. How did you rationalize her decision at that moment?

We had done this scene where she gets to kind of see herself in him. He is the youngest member of the Atreides. He is passed over, brushed into the corner, and develops a relationship with Tula that I think echoes her relationship with Lila later on, in Tula being the older sister that she always wanted and didn't get. I think by the end of the massacre, when Albert appears, she's forgotten that he's there.

To be honest, I think that the decision to inject Orry is one of self-protection and survival. I think she's very fearful of her own safety once he sees what she's done. And I think Albert doesn't pose a threat. It's kind of, "So long as I survive, you don't hurt me, you can go."

When Tula goes back to the Harkonnens after this, they won't even let her take accountability for it because they blame Valya. How did that sort of impulse for them to frame Tula as the "good" sister affect how you approached her?

I do think the sisters are constantly being contrasted. I think they are very different, I think they both like their differences. I think they are both proud of their differences and also really envy the other's differences.

Tula being the good sister — I heard a phrase when I was prepping of like, "The youngest child raises themselves," and that's kind of what I brought through. I didn't see her so much as being good, but I just thought she was never causing any friction. She did her own thing, glided through.

Something I held onto was when Valya and Tula are discussing the acolytes earlier in the season, and Valya describes Lila as a little lamb lost in the woods, Tula really resonates with it. She's like, "I was like that." And that was an image that I knew was important. I knew I had to try and embody that, because Tula needs to be able to recognize that in herself later. I also had in mind "a wolf in sheep's clothing," so I wanted to braid that through.

I know that you and Olivia Williams didn't film together at all — what did preparing to play a younger Tula look like on your end?

I had about two months' prep before stepping on set. I'm Irish, so I'm not speaking in my own accent, whereas Olivia is, so I started there in terms of just specifying intonation and really listening to her podcast, being kind of sneaky and sly. I didn't tell her that I'd done that, though.

Then I got to Budapest, and Olivia really kindly carved time out of her crazy schedule, and we met and talked about Tula. She'd already begun work at that stage. I think once you begin playing a character, the sense of knowing them becomes much stronger. It feels a bit more innate because you're living within them.

But even still, she was incredibly generous having already been working on this character. She didn't stake a claim on Tula in a way that I am just really thankful for.

When we were talking, it was almost like Tula was sitting on the table in front of us and we were both chipping in. She obviously had to do such a huge amount of imaginative work. She doesn't play the younger Tula scenes, whereas I get to live through them and react within them. She has to also track what that does to a person, and how to they process that.

"Dune: Prophecy" airs Sunday nights at 9 p.m. ET/6 p.m. PT on HBO, and is streaming on Max.