[This story contains spoilers for Yellowstone.]

There’s a moment in the latest Yellowstone episode where viewers likely held their breath while watching Beth Dutton.

It’s not the first time it’s happened on the hit Taylor Sheridan-created neo-Western saga, but the operatic feud between Dutton siblings Beth, played by Kelly Reilly, and Jamie, played by Wes Bentley, nearly reached a tragic crescendo in “Horses in Heaven.” In the fourth episode of the fifth season — which follows Kevin Costner’s Montana cattle rancher John Dutton as he becomes Montana governor — Jamie came this close to intentionally running over Beth with his car after a relationship-altering argument.

“I have the luxury of saying Taylor Sheridan’s words, which are weapons — sometimes they’re prayers, and sometimes they’re screams,” Reilly tells The Hollywood Reporter of her one-of-a-kind character on the hit Paramount Network series. “It’s hard to explain Beth or sum her up. I could talk about her for hours. She’s probably the most fascinating character I’ve ever played. In my brain, she certainly takes up a lot of space.”

Beth Dutton has blazed her path into the television lexicon. The no-holds-barred only daughter of the Dutton family has been described as ruthless yet unbreakable, given the trauma she bears and the vengeance she enacts for the benefit of her father and the Yellowstone ranch. Reilly says she was attracted to the character because she had never read anyone quite like her. “Um, complicated. I’d probably start there,” is how she describes her.

“It took me a long time to access her and fully understand her,” she says. “Many hours back in season one before we started filming, I would just be on the phone with Taylor listening to him. I have probably three notebooks full of notes about his vision of her and her history.”

Sheridan, who is in the midst of creating a TV empire that includes Yellowstone spinoffs and prequels, is steeped in knowledge about the Dutton family and fictional world he created, and Reilly says she gained a visceral understanding of Beth from their conversations and from reading the first few episodes.

“I have never read a character like her and was energized by her irreverence and her danger and her recklessness but also her pain. He draws that really beautifully,” she says. “And I knew that to inhabit all of that, for her to resonate or command any sort of emotional response, those notes had to all be equal in her. I think she’s a storm. She’s weather. And there’s something so unapologetic about her that it’s a fantasy, right? You and I wouldn’t get away with speaking the way she speaks or doing some of the things she [does]. So it’s a heightened reality of, wouldn’t that be wonderful if sometimes I could just say what I think?”

The reason for Jamie’s near-hit-and-run attack on Beth is etched deep into the Dutton siblings’ history. But the hatred reared back to the surface after Beth — who had just been arrested for impulsively, and violently, assaulting a woman at a bar for hitting on her husband Rip (Cole Hauser) — is being driven home from jail by her lawyer brother and eyes a toddler’s car seat in Jamie’s car. While viewers have known that Jamie is a father to a young boy, he has kept that fact a secret from his family. And the betrayal sets Beth into a rage, as she questions how fate could have given him a son after what he did to her when they were teenagers.

“You have my womb cut out of me, and God gave you a boy?” she asks, shaking with anger and shock, and referencing how she, as a scared and pregnant teen, turned to her brother for help and he, in turn, took her to get a hysterectomy, instead of to an abortion clinic and without her consent. In the car, Beth hits her brother and nearly sends them off the road. And when Jamie tells Beth that taking her to that clinic is his greatest regret, she promises to rob him of fatherhood: “Next time you see him, you can kiss him goodbye, because he’s as good as gone.”

That’s when Jamie gets back into the car and releases a scream he has been swallowing ever since his sister began to blackmail him over his season four finale choice, where he murdered his biological father to save himself. He speeds his car towards Beth, close enough that if she didn’t step aside at the last minute, he just might have hit her.

“Beth didn’t have a choice,” explains Reilly when speaking about the trauma that has driven Beth’s hatred for her brother ever since the show began. “This is a character who was a teen when she got pregnant, and she wasn’t able to go to her father, and her mother is no longer alive. She’s so afraid of shaming or disappointing her father, so she went to Jamie, who made a terrible mistake because he also didn’t want the word to get out about the high-ranking John Dutton’s [daughter having an abortion], so he took her to a place where nobody would know about it, and she trusted him and made a terrible, awful, tragic mistake.”

The event was revealed in flashbacks in season three, finally explaining the tension long simmering between the two siblings. And though their hatred, especially Beth’s toward Jamie, is apparent to everyone, Beth has never shared with anyone what Jamie did. “She doesn’t talk about what happened for many reasons. One of them would be she knows that Rip would kill him,” says Reilly, diving into Beth’s psyche. “But it’s not just about that. There’s something about this secret that is tied in [to losing their mother].”

As has also been explored in flashbacks, the Dutton family matriarch (played by Gretchen Mol) died during a horse riding accident while out with a young Beth and her other living brother, Kayce (Luke Grimes). Beth’s mother unfairly blamed Beth for the horse bucking and then falling on the mother, and Beth, in turn, has always blamed herself for her mother’s death.

“I actually think that Jamie blames Beth for the death of their mother — so does Beth, blame herself,” explains Reilly. “But more importantly, I would actually say [about their relationship], is that Beth believes that Jamie is the biggest potential threat to her father. He’s already shown it several times. And if there’s anything that is worth killing him for or getting rid of him for, it’s if he threatens, or re-threatens, her father, and the ranch.”

When it comes down to it, does Reilly think Beth has it in her to actually kill her brother, as she has threatened several times? “Good question, I’d have to think about it,” she says. “When I’m in the pit of her hatred and her rage and her pain, yes. It’s that potent and painful for her. But, I don’t know. She had an opportunity to do it, and she didn’t.”

The Yellowstone cast has praised Sheridan for tackling real-world issues within the Dutton family drama, and Reilly highlights how Beth’s story — which is also now airing in a post-Roe v. Wade America — highlights a harsh reality of what was happening in the 1970s and 1980 to Native women. She hopes that will resonate by exploring the complicated trauma Beth lives with, as she forever grieves that her choice of being able to carry a child was taken away from her.

“The tragedy for me in this story is that in the reservations, hysterectomies were carried out with young Native girls and women who were going in to get their tonsils removed or their appendix taken out. They were forced into sterilization, without their permission,” she says. “This happens to Beth, this obviously very privileged white girl, but it was happening all the time to Native women. Taylor highlights a lot of Native American and Indigenous stories and themes in the show, and he puts that on Beth. And, psychologically, Beth’s point of view is that it’s unforgivable. And the fact that it was her brother who made this decision — whether he made it out of ignorance, youth, stupidity, or something darker, we don’t know yet — but Beth considers that to be a huge betrayal, and she’s not someone who has come to peace with that.”

She adds, “Beth literally says, ‘The sting never fades with me.’ She really never forgives anybody. That’s the burden of the character, right there. It’s painful.”

With such a large audience tuning into Yellowstone — the premiere broke a ratings record with more than 12 million live-plus-same-day viewers — the British actress says she’s very aware of how many people are watching. “It’s an enormous beast now,” she says of the show. And while she agrees with fans that it’s a shame for the show to not have been included prominently in the 2022 Emmys conversation, the show’s popularity speaks for itself. “I don’t really know why we’re not in that [Emmys conversation], but it’s OK. The work is what matters, and I’m really proud of the show, proud to be part of it,” she says. “The fact that this show has been taken into the sort of psyche of America, I try and observe it but with a distance. Right now, I’m filming in London so I do feel very removed — they’re still in season three, I think, over here — but I am aware of the energy. The fans of the show are so vocal and very passionate, and it creates a really exciting platform for us all, and a responsibility, I suppose.”