She's a beautiful witch unaware of the extraordinary power she possesses; he's a good-looking (of course) vampire inexplicably drawn to her and together they're on a mission to find an ancient manuscript and save the "creature world" hiding in plain sight from the rest of us.
Ho hum, here we go again – at least that's what it's tempting to think but A Discovery of Witches, which launches SKY's new SoHo2 channel tomorrow night , is a cut above your average witch-loves-vampire supernatural historical romance.
It is, believe it or not, tempered with a good dose of realism.
Perhaps that's because the writer of the book the TV series is based on genuinely knows her stuff. Armed with three university degrees and the cache of actually having studied at Oxford University, Deborah Harkness is a respected academic who's thoroughly researched the history of alchemy, magic, the occult and science.
Before she wrote A Discovery of Witches, the first of the All Souls Trilogy, her previous publications included a study into John Dee, mathematician, astronomer, astrologer and advisor to Queen Elizabeth I, and a book about Elizabethan London's impact on the "social foundations of the scientific revolution".
It means the Fulbright scholar really has sat in Oxford's Bodleian Library doing real research. No wonder Oxford – and the Bodleian – looks so authentic and enticing in A Discovery of Witches' early and eerie scenes.
When she's not, as she does now, travelling the world promoting her books or serving as executive producer on the television series, you'll find Harkness back at the University of Southern California teaching the undergraduate paper An Introduction to Historical Methods.
But life hasn't been the same since 2011 when A Discovery of Witches became an international bestseller. Back then, she was an academic who, struck by the number of blockbuster books about witches, magic and vampires, decided to challenge herself to see if she could write one.
After all, Harkness had folders and cabinets full of material to draw upon so it was easier to come up with back stories for characters who (spoiler alert) travel back in time and get right the details of what they find when they get there.
The story begins with visiting American historian Diana Bishop (Teresa Palmer) lecturing at Oxford before unexpectedly happening across a bewitched manuscript, the mysterious Ashmole 782. Suddenly, she's surrounded by other witches, demons and vampires notably 1500-year-old French bloodsucker Matthew Clairmont (Matthew Goode) who want the book. Trouble is it's vanished again.
"Historically, these types of characters are monsters that we project the anxieties of the moment onto; they are characters that provide a way for us to think through issues of difference," says Harkness of their continued appeal. "We are both fascinated by people who are different but we can also fear people who are different and it's that dynamic that has always been part of their story."
And, she adds, we're all a little riveted by the supernatural and the possibility that witches and demons just might exist.
The film rights to A Discovery of Witches were quickly snapped up but equally quickly, it became obvious the complex story wouldn't be condensed into a 90-minute film. Those rights lapsed; Harkness wrote two more books, then the BBC's Jane Tranter called her to talk about book one as a television series. Harkness liked that Tranter, executive vice-president of programming and production at BBC Worldwide in Los Angeles, had adapted Charles Dickens books for TV.
"I thought, 'well, if she can do Charles Dickens, she can do mine!'"
Harkness became executive producer for the eight-part series, but says it didn't mean she had a great deal of control over the adaptation.
"I don't even have control over my own hair," she laughs, down the line from a London hotel room. "So, no, I didn't have a lot of control over things like the casting but I was part of a collaborative team which was great fun for someone who normally works alone.
"It was amazing to show up to the screening and see your imaginary friends up there. Then I got to sit in a hotel room, like a normal person, and actually watch an episode because it just happened to be on the television. That's when it really hit me that this was magical."
Is it magical timing that Harkness is launching a fourth book, Time's Convert, at the same time A Discovery of Witches is being screened to positive reviews, solid ratings and a nomination for the UK's prestigious National Television Awards in January?
She agrees she couldn't have planned it better had she tried, but says it's purely serendipity. Time's Convert sticks with some of the characters from the All Souls Trilogy; in this case, Marcus Whitmore, son of Matthew de Clermont, and his girlfriend Phoebe Taylor who decides to join him in eternal bloodlust. While Phoebe is transitioning, Marcus remembers his own journey which sees him fighting in the American Revolutionary War, visiting France during its Revolution and spending time in New Orleans.
For Harkness, that meant being a student again; the Enlightenment – with its revolutions and move toward democracy – isn't her area at all.
"But I love inventing characters, exploring them and what's shaped them so it seemed like an obvious next step to borrow more into the lives of Marcus and Phoebe but the challenge was that the 18th century world is very different and I wanted to get it down in a way that was consistent with how I'd written about the 16th century.
"I also have colleagues who specialise in the 18th century and I wanted to be able to keep walking past their office doors with my head held high."
Haven't spent a lifetime trawling around in the past, wouldn't she like to visit? It's a definite no.
"Life was very, very hard and everyone thinks if they went back, they'd be living in a comfortable house with enough food but the reality is that most people did not live that life," Harkness says. "I have come to take certain things for granted about freedom of movement and my right to occupy space in a room as a woman. Those things would not have been possible and as a woman who has a lot of opinions, well, that would have been a very difficult position to occupy back then."
• A Discovery of Witches launches SKY's SoHo2 on Wednesday November 7 at 8.30pm; episodes will also be available on NEON. Time's Convert (Hachette, $35) is out now.