Carroll loves a trivia night and she starts telling me about one where their table decided to dress up like Audrey Hepburn. And how she was on a book tour with another friend of hers, and how this friend helped her choose her costume whenever they had free time.

“And that was the spark for Liane’s scene in Big Little Lies - the fateful trivia night where they’re dressed as Audrey Hepburn.” Liane, yes, her close friend author Liane Moriarty.

I was scheduled to interview Moriarty two days later, and we joked about how it might have been easier if we’d all just caught up somewhere with a bottle of wine and an afternoon to waste and talked about friends and families and books and Nicole Kidman and how we all manage the juggle.

It’s these regular suburban worlds that have provided a backdrop to Moriarty’s novels and Carroll’s are no different.

She might not be as big a name as her friend but her books are also based in the everyday. From office romance, to hidden secrets, to the power of female friendships, her previous seven novels have touched on the idea of belonging and finding your place in the world. She adores the writing of Marian Keyes, Maeve Binchy and Maggie O’Farrell - Carroll was born and raised in Ireland and moved to Sydney in 1995 - and that’s the genre she fits in, she says.

Or did.

Her latest book The Missing Pieces of Sophie McCarthy is not one of those books. Think Gone Girl, think The Woman in the Window.

Moriarty says the book is "intriguing, compelling and impossible to put down". A nice plug from a mate if ever there was one.

Sophie McCarthy is a book with a dark twist, an unreliable narrator, and an undercurrent of suspense where you’re second guessing yourself at every moment.

“This is the first time I've written a character like this,” Carroll says. “In my previous books they're very much likable characters, they might have had lots of issues, but the reader knew they were likable. It was quite a shift to write a character who wasn't.”

Indeed Sophie is a right piece of work. It’s hard not to give too much away but she’s suffering from chronic pain due to a car accident and is in a twisted relationship that has come out of that incident. She’s an office tyrant, a bully, and at times you find yourself in her camp. But not often.

“I don’t like her either,” Carroll says, “but I wanted certain parts of her to be admirable. I wanted her to be someone we all know.

“It was very important to me that she was realistic … I didn't want her to be a psychopath … I wanted her to be an everyday person who pushes those boundaries of acceptable behaviour.

“We all know people like that and sometimes we can even recognise some of those traits in ourselves.”

Carroll says she knew from the first page this book would be different and so she’s published it under the name B.M Carroll.

“I think you need to let your readers know, your publisher know, and yourself know, if you're writing something different, otherwise you would slip back into what you know and I was trying to avoid that.”

She’s written the book in several voices, from Sophie, to her partner, to her partner’s young daughter, to name a few.

“I think I broke every rule doing that,” she says. “It became quite a problem during the editing process but it was a story I just had to tell this way, it’s how the story came out.”

Carroll worked in the finance sector, in IT, in Ireland, and came to Australia with her boyfriend, now husband, Rob. She worked in the corporate world while her children were young, writing at the same time, but she quickly realised she couldn’t “have it all”.

Her first book Executive Affair was picked up quite quickly, she says, and she was offered a three-book deal. Her eldest son, now 16, was a newborn at the time and she took the chance to write full time.

“And now he’s reading my drafts, coming out of his room to tell me about Sophie and how he can’t read her and he’s not sure whether or not he should like her.”

The Missing Pieces of Sophie McCarthy, by B.M. Carroll. Michael Joseph, $32.99.

Ber Carroll will be speaking at Harry Hartog Bookseller, Westfield Woden, on Thursday October 4, at 6pm.