Sam Heughan and Caitriona Balfe Sam Heughan and Caitriona Balfe

Step onto the set of new Starz drama Outlander, deep in the countryside north of Glasgow, and it's easy to relate to series heroine Claire Randall (Caitriona Balfe), a married, English World War II combat nurse suddenly — and mysteriously — thrust back in time to strife-torn 1743 Scotland.

Kilt-clad men and corseted women mingle in the smoky candlelight. Two Irish wolfhounds loll by a massive, blackened fireplace as snippets of Gaelic drift through the stale castle air. And when director John Dahl yells, "Action!" Claire watches in horror as a burly Scottish clansman lands punch after punch on a young Highlander named Jamie Fraser (Sam Heughan), who has valiantly volunteered to endure the punishment for a girl sentenced to a beating. "This is barbarous," she hisses. No, it's just 18th-century justice in action.

"Claire is a fish out of water," Balfe says during a break in filming. "She's incredibly fierce, passionate, stubborn — a very modern woman even for the 1940s, so what's wonderful about her going back to the 1700s is that she's also representing women of our time."

This fiery strength — not to mention the time-bending passion that soon ignites between Claire and Jamie — is the heart of what helped make Outlander a worldwide phenomenon. Since 1991, Diana Gabaldon's wildly popular book series has sold 25 million copies, and the eighth novel, Written in My Own Heart's Blood, debuted at No. 1 on the New York Times best-seller list last June. And with innumerable blogs, websites, Tumblrs, and Facebook pages devoted to all things Outlander, the global fan community just keeps growing. Now, the first treasured tome in the series is finally coming to the small screen.

"The project was caught in movie-development hell for a long time, but no one had ever pitched it as a series," says Starz CEO Chris Albrecht. "The fact that there were already so many ardent female fans, and the fact that women are not only great viewers of television but also great users of social media, gave me the confidence [to go forward]."

A faithful script by executive producer Ronald D. Moore (Battlestar Galactica), whose wife, Terry Dresbach, introduced him to the books, helped finalize the deal. "It was the first script based on Outlander that didn't make me either turn white or burst into flames," Gabaldon says. "It caught the spirit and the voice of the books."

To bring the story to life, the production headed straight to Scotland. "They have the castles, the landscapes, the artisans who make swords and weapons of that time," says Moore. Some exteriors were shot at Doune Castle, which dates to the 14th century and was also featured in Monty Python and the Holy Grail. For the interiors, producers converted an unused electronics factory into a studio complex. The space houses two soundstages measuring 17,000 and 10,000 square feet; an armory; a props warehouse; a costume shop overflowing with tartans designed specifically for the show and made with local dyes; and a classroom where an expert coaches the actors in Gaelic. "Everyone speaking authentic Gaelic helps me with my character," Balfe says of the language, used often in the series, without subtitles. "It makes me feel like I am truly in a world where I don't know what's going on around me."

But all this authenticity comes at a price. "It is a large budget," admits Albrecht. "It's not the most expensive show that's been on Starz, though I have to say, there's not been a better looking show on Starz at any price." And with genre-smashing adaptations like Game of Thrones already having paved the way — and getting plenty of Emmy love — Outlander could prove to be a game-changer for the cable network best known for such culty, but not exactly groundbreaking, series as Spartacus and Magic City.

While Game of Thrones takes place in imaginary lands, Outlander is rooted in real history. Gabaldon sets the epic romance against the backdrop of war-torn Scotland, filled with sketchy local lawmen called the Scottish Watch, rebels known as Jacobites, who are plotting to restore a Catholic king to the English throne, and a cruel occupying force of British redcoats. The nastiest of the Englishmen is army captain Black Jack Randall, who happens to be an ancestor (and lookalike) of Claire's 20th-century husband, Frank (Tobias Menzies, who plays both roles) — the man she's desperately trying to return to in Outlander's early episodes. 

In a departure from the books, Claire's relationship with Frank in the series is much more sensual and strong. "We want [the audience] to root for her and Frank," says Moore. "Yet at the same time she starts to love Jamie. It's difficult, conflicted."

Things get even more complicated when Claire and Jamie are forced to marry by Jamie's uncles, Colum (Gary Lewis) and Dougal Mackenzie (Graham McTavish), for her protection. She's suspected of being a spy because she's an outlander (one of the many derogatory names Scots used for English people) and a witch because of her medical skills. "Claire has principles," Gabaldon explains. "She can't let anyone suffer or die for lack of medical care that she can offer. But people don't understand what she's doing and think it's magic. It becomes a clash of science and religion."

Unfortunately, the marriage doesn't protect Claire from the brutal suspicions of the Highlanders, forcing her and Jamie to go on the run. "There's a lot of distance traveled, not only in Scotland, but in time," says Heughan. "Things get sexy." And dark.

Jack and Jamie share a painful history that has left the evil Englishman dangerously obsessed with the young Scot. "Jack is a sadist," says Menzies. "He has no moral compass, no guilt." And if it is Claire who needs help in the beginning of the series' 16-episode first season — which will air in two blocks of eight, with a September midseason finale and early 2015 return — it's Jamie who is in jeopardy later on.

"Claire loves him so fiercely that she won't stop at anything to save him," Balfe says. And Starz is banking on fans of the novel to love the lush, lusty, and action-packed adaptation just as fiercely — as well as to bring in new fans. "This is one of those unique shows, for me, where the end result is even better than I could have envisioned," Albrecht says. "The show makes you want to be Scottish. Or at least have some Scotch."

Outlander premieres Saturday, August 9 at 9/8c on Starz.

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