After seeing an advertisement in an 18th century book that asked for participants in an experiment that would see them living underground for seven years with no human contact, Alix's mind started to whirl with possibility.
Months later, she had written The Warlow Experiment, which is now out on paperback and was recently named Waterstone's Welsh Book of the Month.
"The book came from a quotation I saw, something I read in an 18th century book called the Annual Register – it tells you everything that happens in a year, apparently they still publish it," she explained.
"I found this story that said a man had advertised for somebody to live underground for seven years and not have any contact with anyone. It would be a luxurious apartment underground, with fire and water and everything they need, they just can't see or contact anybody. Only one person applied for this.
"The first thing I did was go to the Annual Register but I couldn't find anything reported on what happened. I had no idea if he survived or what happened. It was completely strange."
Alix said at the time, she became quite obsessed about it and asked everyone she met what they thought.
"I wanted to work out what it was like for the man underground and why he would want to do it, but also why the man put the advert out in the first place," she added.
"I became more and more sympathetic to the man underground as I wrote it even though he is quite a brute. Borders are an interesting place so even though I live on the Welsh borders near Bishop's Castle I wanted to set the book further down, nearer to Herefordshire."
The book will be sold at Art & Artisan Books in Bishop's Castle - call Rachel on 01588 505053 to order.
Visit alixnathan.com/ for more information.