In The Dead House (Arcade, May), a supernatural thriller, O’Callaghan crafts a contemporary ghost story set in rural Ireland.

You’ve written that this story has been in your bones for decades. Could you expand on that?

I carried it around in my head long before I ever seriously thought of writing as something I could possibly do. For so long, actually, that I’m not really sure where the seeds of the idea came from. But I have just always loved ghost stories. I love to read them, and I love to hear them being told, and I suppose it was inevitable that I’d eventually start making up stories of my own. There’s such a rich tradition of the supernatural tale in Irish literature, and the ghost story always seemed such a part of the social fabric, certainly within the world I knew.

Did anyone in your family influence you?

The stories that actually changed my life were ones told to me by my grandmother, sitting at the fireside as a very young child, and it was these, told to me on cold white days in an otherwise silent house and in a voice old as dirt and full of weather, that instilled in me a passion for narrative. I write today because of those old stories, and I carry that voice inside me, always. I remember listening to her talk about the fairies or the banshee, or the many strange things she’d either seen or heard tell of. She made the natural and supernatural not seem so far apart, and I think I’ve carried at least some sense of that with me as I’ve grown.

Was there a local legend that inspired the plot?

No. But over the years, I’ve heard all kinds of yarns about Ouija boards and the dangers involved in dabbling with forces beyond our understanding. Also, in Ireland we are an odd mix of strict Catholicism underlaid with some lingering pagan concessions. Genetic memory is hard to overcome, and a tendency towards superstition is part of the native character.

Why make your narrator English?

From the beginning, I knew that the narrator would have to be an outsider—the logical city-dwelling businessman taken out of his element sets everything off-kilter. The Hound of the Baskervilles was an influence. When Sherlock Holmes first hears of the legend of a hound from hell, he is in his comfortable London rooms, and such an idea seems preposterous. But when he and Watson get out on the moors, where fog lingers and sounds are amplified by the wind and the undulations of the landscape, suddenly the story takes a more plausible turn. I wanted a similar counterpoint.