Recovering from the recent death of his wife in a tragic accident, Tony Sheridan goes to stay with his sister-in-law, Lucy, and her husband, long-time friend Matt Prior, at their new home in the country - Otherways. It is a strange, circular, moated house, the only surviving creation of an eccentric and reclusive Edwardian architect. Disturbed by memories of his wife, and a growing attraction to Lucy, Sheridan is also troubled by weird and vivid dreams. He learns that a murder committed at Otherways in 1939 still has a strange and malign power over those living in or near the house, as does a later scandal surrounding the murderer's brother, a nuclear scientist who defected to the Soviet Union. These and other mysteries forewarn Sheridan of disaster as he and Lucy embark on a passionate affair.

But disaster, when it strikes, is far worse than a wrecked marriage or a friendship betrayed. In uncovering the truth about Otherways, Sheridan realises too late that he is merely adding to the list of its victims - and that those closest to him may soon be among them.

You could say there’s a lot of circularity in the plots of my novels, but nowhere is this more explicit than in Set in Stone. It was a visit to A La Ronde, a National Trust property near Exmouth, in Devon, that first made me think about the possibilities that a literally circular house offered as the setting for a metaphorically circular story. Do go and see A La Ronde if you can.

Throughout this book, I’m playing around with time and place quite consciously. Otherways, the fictional house at the centre of the action, is architecturally deceptive and is set in a part of County Rutland that is geographically deceptive as well. The creation of the Rutland Water reservoir in the 1970s drowned a lot of history along with a chunk of fertile farmland. It seemed to me that the area possessed a haunted quality as a result of this and that too is fed into the story in the form of supernatural elements that reflect how I believe we should view what people experience when they think they see ghosts.

The world of espionage is also associated with deception and I suppose that made it a natural fit with the other themes in the story. It also gave me the opportunity to investigate the lives and beliefs of some of the spies whose acts of (apparent) treachery in the post-war years became such a recurring feature of the contest between western democracy and Soviet communism.

Above all, the name of the house, Otherways, provides the motif for the whole: events are never inevitable; matters could always turn out differently if only one could foresee all the consequences of specific actions. But that, of course, is something mere humans find almost impossible.

Perhaps appropriately in view of all this, the conclusion of Set in Stone has puzzled more readers than any other book I’ve written. I sometimes wish I’d made it a little clearer what the significance was of  the letter Tony Sheridan receives at the end - its contents and its postmark - but on reflection I feel that might spoil the fun. And that would never do!