In times of overwhelming change, tradition can be vital for survival. Knowing how things were done before, understanding what still works, and discarding what doesn’t can be a crucial part of moving forward. This is what brings Harrison Ford and Helen Mirren’s longtime frontier couple to the Yellowstone Dutton Ranch in the upcoming series 1923. Tradition—and unstoppable change.

Set a century before Kevin Costner’s John Dutton III holds together his family’s sprawling Montana empire in America’s most popular TV show, the contemporary Yellowstone series, this latest spin-off from creator Taylor Sheridan explores what life was like for the second and third generation of Duttons to work that land. They find themselves turning back to the first generation for guidance.

A lot has changed in the 40 years since James and Margaret Dutton (played by Tim McGraw and Faith Hill in the predecessor series, 1883) brought their family to this territory. Exactly what became of them by the time of 1923 is a mystery the show will reveal, but suffice to say their children, now in their late 30s and 40s, and grandchildren, now in their 20s, have come to rely on a new matriarch and patriarch as they confront the rise of mechanization, the growth of local government, and competition for resources from other ranchers. Their father’s brother, Jacob Dutton (Ford), and his wife, Cara (Mirren), now lead the family.

“He’s the silverback,” Ford tells Vanity Fair for this exclusive first look at the show, which debuts December 18 on Paramount+. “He’s responsible for that branch of the family. These are two people with a very strong bond to each other who are facing really complicated circumstances.”

Their strength, according to Mirren, is experience. “You need someone who is capable of making decisions, and hopefully making the right decisions, but at least making a decision and going with it—in other words, a leader,” she says. “That’s what has propelled them into this position of running the ranch, running the family, being the linchpin around whom, at this moment in time, the family revolves.”

Mirren says she wanted Cara to represent another aspect of rugged individualism that has long-defined American society. “I see Cara as an immigrant,” says the British-born actress. “One of the things I very strongly wanted was that she would speak with an Irish accent, not with an American accent. It’s always slightly annoyed me with Westerns that you have all these people speaking with modern American accents when in fact so many of them were fairly recent immigrants.”

The Oscar winner even has a full backstory for Cara: “The big Irish immigration to America, because of the potato famine, was in the late 19th century. That absolutely chronologically works for Cara. She’s now in her late 60s, we imagine. So she would’ve come, I think, as a young woman from Ireland. I think that’s one of the extraordinary elements of America. The people who arrived, and are still arriving, are people with enormous resilience and enormous courage and independence.”

Ford said Jacob and Cara have been married for about four decades, which roughly corresponds to the last time the two appeared together onscreen, in 1986’s The Mosquito Coast, also playing a couple who travel to remote and dangerous untamed lands. The matriarch and patriarch of that family were often at odds. In 1923, they are each other’s everything.

“They’ve been married a long time. They haven’t had children, so they haven’t had the sense of children holding them together,” Mirren says. Time has forged a relationship that might best be described as sturdy. “That really is what it becomes, isn’t it?” Mirren says. “An incredible partnership where you can be honest with each other, and your love and support of each other is total, but at the same time you are no longer blinded by love or by lust. You’re much more clear-eyed about your relationship, but the relationship becomes all the stronger for that very reason.”

And there’s still passion. “Their lives are totally wrapped up in each other,” Ford says. “There’s very little that sustains them other than themselves and the hard work and investment they put into their future and their family. It is a tough life, and it’s full of not just physical challenges but moral ones as well.”

That’s the curious thing about the Duttons. They’re the central figures in the Yellowstone story line, but you can’t always call them heroic. They prioritize honor, integrity, and loyalty, but they can also be ruthless when pushed, creating a tension that’s central to this franchise’s immense appeal. Costner’s family, six generations removed from the ranch’s original settlers, still sometimes operate like it’s the Wild West, with Darwinism superseding any other law that may be on the books.

That was true even as society and government took early root in the frontier, so that Dutton cunning will also reveal itself in 1923. “You’re very close to the bone here. The story is told in a very honest and straightforward way. There’s no apology for what becomes necessary to do,” Ford says. “There’s a very strong moral context that’s…” He hesitates, and chuckles before finally settling on an adjective: “Frangible.”

However brittle the Dutton morality may be, the world of Yellowstone has always presented it as a necessary evil. Kill or be killed, especially in hard times—and they’re always in hard times. “The Duttons live by a code of behavior that they set for themselves and it requires complicated moral and ethical judgment,” Ford says. “It’s not just the physical life that’s hard. The challenges that they face from modernity, the challenges to their way of life, to their freedom and the opportunities that they’ve enjoyed, is a big part of the story. The upcoming Depression and all of the pressures, economic and social, are leading up to this very volatile time in American history.”

The brutality of it all, and even the unfairness sometimes, is part of the texture of the show. “It’s a real investigation of American history,” Mirren says.

Times may change, and so might the makeup of the family, but there are constants to 1923 that fans of the show will recognize. “Look, the Dutton families have similar genetics,” says David Glasser, executive producer of 1923, as well as 1883 and Yellowstone. “They are tough. They are not without heart and soul. They are about family and protecting their legacy, protecting the land that they own. You’ll see there’s a lot of similarities in the men and women of the ranch.”

So who are those men and women this time? There are some cast members and characters whose involvement remains under wraps, but here are a few who can be revealed…

When 1923 begins, Jacob and Cara Dutton have already made themselves at home as the new patriarch and matriarch. Whatever happened to James and Margaret, it was long ago. “We’re gonna pick up with them having been there for a while,” Glasser says. “They’ve cemented their [roles] in the town.”

John Dutton Sr. (played by Hightown’s James Badge Dale), was just a little boy in 1883, but now in middle age he is the right-hand manager of the ranch alongside his Uncle Jacob. While they take care of the cattle and the land, his wife, Emma (played Marley Shelton), helps maintain the household and the family with Cara.

Their son, Jack (played by Chilling Adventures of Sabrina’s Darren Mann) is following the same path as his father, toiling as a ranch hand to earn his place in the hierarchy. One day, he will inherit the whole kingdom, as will his descendants. Jack is the great-grandfather of Costner’s character.

Among the other figures inhabiting Yellowstone in this era are Elizabeth Strafford (played by Michelle Randolph), a firebrand who is preparing to marry Jack, and Brian Geraghty as Zane, who is not a blood member of the family but remains one of their most loyal foremen.

In all its iterations, Yellowstone has often acknowledged that the settlers who came to control this Montana land are not actually its first or only inhabitants. Even in the present-day series, there is enduring conflict and unresolved disputes between the tribes of the region and the Dutton family. Indigenous life will factor into 1923 too. “As [Sheridan] has always done in his other worlds, Native American stories and stories of the time period will play a part in this show,” Glasser says.

As part of that story line, Aminah Nieves plays Teonna, a young woman who has been forced to attend a government-run boarding school, the kind now seen as a shameful part of America’s past. Such schools were infamous for their brutal practices and the way they deliberately suppressed traditional languages and cultural practices in Indigenous children, who were often removed from their families and communities.

Among the primary threats to the Duttons is a group known as “the sheep men,” rival ranchers who rely on the same grassland as the Duttons, and they’re willing to fight them for it. Their leader is Banner Creighton, a Scottish shepherd played by Game of Thrones’ Jerome Flynn.

The sheep men are fighting for their survival too, and Jacob and Cara Dutton’s responsibility is to their own family. While Costner’s generation of Duttons are extremely wealthy, the Duttons of a century ago were far more hardscrabble. “They can lose it all in a season,” Ford says. “They’re up against weather, the economy, the influx of railroads, and the change in the cattle business. It’s a complicated time. It’s a volatile time. They are land-rich, but they are cash-poor because everything is put back into the business, into the ranch. Everything is hard fought for. I don’t think of them as rich. I think of them as having a degree of power based on their historical presence in the area based on hard work.”

One key to their power is the women of the family, who are sometimes more open-minded and ready to embrace changes that will actually improve their lives. “There is a recognition, especially I think from Cara, that change is coming and you have got to change with it. You’ve got to,” Mirren says. “You’ve got to learn, you can’t imagine that things will go on forever the way they were. She has the ability to adapt, to change. I think that is very true of women in general. Women tend to be more adaptable, more open to new ideas.”

1923 is another chapter in the Yellowstone story, but each segment adds up to a broader study of the pressures people face and the complex ways they react to them, sometimes improving things, sometimes making them worse. 

“A lot of America seems to be, in my mind, unfinished business,” Ford says. “This is a story about the development of the country—and the nature and personality of this country is very much a product of the circumstances of this period of time.”