How does a historical epic featuring time travel, wars and a sizzling love triangle spanning two centuries top itself in its third season?

Outlander star Caitriona Balfe (left) - who won Golden Globe nominations both this and last year for her role as its spirited heroine Claire - says the new season of the Starz show will continue with its fantastical narrative.

But it will remain grounded in the realistic, fully-formed characters that have made it a hit with fans, she adds.

Based on the best-selling historical time-travel novels by Diana Gabaldon, the story begins with Claire, a British World War II nurse, going on honeymoon in Scotland with her husband, Frank (Tobias Menzies), in 1945.

When she comes across some mystical stones, she accidentally jumps back in time to 1743, where she gets caught up in the Scottish Jacobite rebellion against the English, in the process falling in love with dashing Scotsman Jamie (Sam Heughan) as both are hunted by a villainous English soldier named Black Jack (also played by Menzies).

Then Claire becomes pregnant by Jamie before she is unwittingly zapped back to the 1940s, where she now has to repair her marriage to Frank.

This labyrinthine plot routinely defies the laws of space and time, but speaking to The Straits Times and other press in Los Angeles last month, Balfe, a 37-year-old Irish actress and model, says the threedimensionality of these characters is very much true to life.

And she thinks this may be why the show seems to appeal to both men and women, even though many critics have commended its feminist depiction of Claire and her unapologetic sexuality.

"One thing we've always said about our show is that Claire is sort of at the centre, but it's not just her - it's the fully-formed characters of Jamie and Frank as well as Black Jack.

"Whereas on some shows, maybe you have a central male character and surrounding him are more two-dimensional versions of women.

"We've made all of our characters fully formed and they all have great depth, so what you get is a great balanced look at relationships. I think that's why so many people relate to it, because it's giving you a realistic version of people," she says.

When it comes to the action and plot twists, the new season, which debuted last month on Netflix in Singapore, with new episodes released on Mondays, is as surprising as Gabaldon's Outlander books. The American author has written eight since 1991, with a ninth in the works (Season 3 is based on the third novel, Voyager).

Heughan, a 37-year-old Scottish actor, says: "I think anyone who's read Diana's books will say, 'Oh, crap. I never saw that coming,' because it's just a sequence of twists and turns. I think that's the great thing about the books and it's a great thing about our show."

The star, who is dating American actress MacKenzie Mauzy, 28, adds: "I'm sure the reason why (the producers) were so hungry to make it is that you're constantly being kept on your toes. I mean, who would have thought we would end up on ships and in Jamaica this season?

"You never know what to expect. And the great thing about it being a time-travelling fantasy is the story can go anywhere, and very frequently does."

After Season 2, viewers who have not read the books will be wondering if and when Claire and Jamie will be reunited.

Executive producers Ronald D. Moore and Maril Davis assure fans that they will, but it will take some time and, meanwhile, each will go through major life changes and heartbreak.

Moore says moving forward, the series will cover the "20 years of their lives" the two spend apart, which will be full of "major moments of drama".

He adds: "It felt like, to do that justice, you had to give it some time and some space so you didn't just brush over it and pretend like nothing had really happened."

Balfe, whose boyfriend is London pub owner Tony McGill, appreciates the fact that the show is not rushing its character development.

"The great gift of doing a series like this is you're given time to really get to know your character and explore different elements.

"I don't know that you get the chance to do that over an extended period of time in many projects."

•Outlander Season 3 is available in Singapore on Netflix.