Toby Regbo, Adelaide Kane, Torrance Coombs

When Adelaide Kane moved from her native Australia to Los Angeles to kick-start an acting career, her life was hardly a royal fairy tale. "I was afraid and homesick and so broke," she remembers over afternoon tea. "I was a nanny full-time to pay my rent."

Three years later, Kane is poised to rule as a breakout star of the fall season, thanks to her leading role as a teenage Mary, Queen of Scots, on The CW's new period drama Reign. The series, which has been given the plum Thursdays-at-9pm time slot following the network's biggest hit, The Vampire Diaries, is already generating plenty of buzz due to its decidedly modern spin on the life of the tragic 16th-century monarch. Mary arrives at the French court prepared to marry Francis (Toby Regbo), the hot, leather-clad future king, in order to secure an alliance between their two countries.

A heroine tailor-made for The CW's predominantly young audience, Mary is headstrong, gorgeous and riddled with teen angst, and she soon discovers that the royal court is as catty and cutthroat as the social circles of Gossip Girl. When the Queen bee isn't dancing to a modern-rock soundtrack at glamorous balls with her BFF ladies-in-waiting, she's caught up in a love triangle with Francis and his roguish illegitimate half-brother, Bash (Torrance Coombs). "My desire was to do a period piece that didn't feel like your mother's," says executive producer Laurie McCarthy. "I felt like there was a way to tell Mary's story as an epic tale of romance in an incredibly high-stakes world. This was a time when who you loved and who you bedded could cost people their lives."

Some critics are, metaphorically speaking, already calling for McCarthy's head because of the artistic license her coming-of-age soap takes with history. Coolly confident playboy Francis was, in reality, a sickly boy, while the dashing Bash didn't even exist. And bearded seer Nostradamus was already in his fifties when he advised French queen Catherine de Medici (Megan Follows), Francis's steely mother, though here he gets a broody heartthrob makeover, courtesy of 35-year-old Canadian actor Rossif Sutherland (Kiefer's half-brother).

Still, McCarthy insists that while Reign may take liberties with some details, it will remain true to the key moments of Mary's life, including — spoiler alert! — her marriage to Francis and his death less than a year later. "We use the architecture of history as a leaping-off point," she says. "The wiggle room is in telling the stories that live in between those big events."

The queen born Mary Stuart has long fascinated McCarthy, who spent a year abroad in Scotland. "She's been nipping at the periphery of my consciousness for a long time," says the veteran producer, whose credits include Ghost Whisperer and Felicity, "and it finally felt like the right time to do this show." Finding the right actress to play the royal, previously embodied on screen by the legendary likes of Katharine Hepburn and Vanessa Redgrave, was a daunting prospect, at least initially. "I was really hunkering down for a long Scarlett O'Hara casting process," McCarthy says with a laugh. "I'm wildly picky, and I had an idea in my mind that I wanted her to be this warrior queen."

Kane, 23, whose biggest previous credit in the States was a role on MTV's Teen Wolf, was the first person she saw and, to McCarthy's shock, the last. "Adelaide's fearless," she raves. "She tried out about six different accents and then shrugged and said, 'It's no big deal, really.' I thought, 'Yes!'"

Rounding out the love triangle are Regbo, a 22-year-old Brit who has worked hard to make his American-series debut ("I had my teeth whitened and my hair dyed blonder," he says with a laugh), and 30-year-old Canadian Coombs, who, having spent a season on The Tudors, knows his way around a costume drama. "I have the most fun role," he claims. "I get to ride horses, do swordplay and cavort with beautiful women. It's a bit of a dream job."

Kane isn't complaining about hers, either. "I'm really looking forward to playing the melodrama of teenage ­romance, because I was very late to the dating game," she says. "The 'I love you' and 'I wanna be with you forever,' I never went through that. I always had my nose in a book."

But the royal agenda features more than just hookups. With Nostradamus warning that Mary will cost Francis his life, Catherine emerges as a formidable nemesis for the young queen, who will soon have more to fear than just a scheming future mother-in-law. A mysterious figure in the pilot who saves Mary from being poisoned will be revealed as a disfigured girl named Clarissa (Katie Boland), who has what McCarthy calls "a very deep bond to the castle and its inhabitants, and her anger could turn toward Mary at a moment's notice." There's also something ominous in the woods. "The death toll will escalate," McCarthy warns. "Blood will be shed." Let it Reign.

Reign premieres Thursday, Oct. 17 at 9/8c on The CW.

For more on the new fall shows like The Originals and The Tomorrow People, pick up this week's issue of TV Guide Magazine, on newsstands Thursday, Sept. 12!

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