The ingredients may be similar to a certain mega-selling thriller, but please do not make the mistake one critic made of comparing Clio Gray's debut novel with "The Da Vinci Code".
"Oh no," she moans, rolling her eyes long -sufferingly when reminded of the critic's description of her novel "Guardians of the Key" as "just as bloody as 'The Da Vinci Code', but much better written."
"It's not like the bloody 'Da Vinci Code'. The only thing they have in common are that they have these religious relics," Clio points out.
"It is kind of annoying because a couple of people have made that same comparison. If the people who like 'Da Vinci Code' read this one, they probably won't like it. It's a bit more literary than that."
It also dispenses with a contemporary setting in favour of a recreation of early-19th century England and a plot set in motion by Napoleon's invasion of Italy.
"Basically it's about the town of Lucca in Italy. It's a city state and they do keep a massive archive of relics and other things," she explains."Among those they have got the Volto Santo, supposedly a true reflection of what Christ looked like. Then, when the city is under threat in the Middle Ages, they took relics out of Lucca and took them to London where there was a big Italian community. This is all documented. There was a Volto Santo cult in Old St Thomas's Church in London."
The hunt for the lost relics begins in earnest when Napoleon declares himself King of Italy and hands out principalities to his sisters. Maria Elisa is given Lucca and being a religious woman wants to know where the Volto Santo is.
"The bad guys are trying to find it, the good guys are trying to find it and you have this one girl caught in the middle," Clio reveals.
"You have fires, suicide, murder and a big chase through the snow at the end."
The innocent girl is Mabel Finchurst, who witnesses the macabre suicide of an Italian exile in a London Church. When her friend, a vagrant boy called Toby is kidnapped, she enlists the help of missing persons finder Whilbert Stroop. The widely read Ms Gray came across Stroop's name and pictured him immediately, and determined to make use of him in her future writing. Anything else of potential interest is filed away in the various files she keeps covering science, literature, nature, expeditions and images.
"It's great, because 20 years of research has finally paid off," Clio adds.
Stroop will make a further appearance later this year in Clio's second novel "The Roaring of the Labyrinth", which moves out of London to a Yorkshire country estate called Astonishment Hall.
"I know from working in the library that people who read crime books of any kind do like series and characters and do like to follow them through," Clio says.
Born in Yorkshire, brought up in Devon and now resident in the East Highlands, Clio reveals the book began as an entry for The Harry Bowling Prize, administered by literary agency MBA in memory of the late author of London family sagas, and requiring writers to submit the first 5000 to 10,000 words of an unpublished novel which had to be set in London. A competition she entered in spite of hjer antipathy to London and other big cities.
"It's really hard to get anything published. Just to get people to read what you have written is really hard," Clio says.
"I had a vague outline of the plot, but nothing concrete. When I won the competition I had to work quite hard on it."
To get round her antipathy towards large cities, Clio decided to set her story in the past, when London was much smaller and more like a modern day small town. Her own home, in the east Highland village of Ballintore, is certainly far removed from big city life.
It is no surprise that Clio decided to write about murder. She has always had a morbid side to her imagination, she says, and recalls one of her teachers calling her mother into school because she was so concerned about something Clio wrote.
She began writing seriously again after moving to the Highlands, and founded HISAC, the Highlands and Islands Short Story Association which now awards an annual prize.
Clio had her own success in short story competitions last year when she won the Scotsman/Orange award with her story "I Should Have Listened Harder", beating 1500 entrants to claim the Â£7500 top prize. Set in a Siberian prison mine and praised by chairman of the judging committee Bernard MacLaverty as "bleak and powerful", the story is now available as a podcast from the Scotsman website.
"The Roaring of the Labyrinth" is due for publication this summer and features a plot which winds from the Black Sea and the creation of the city of Odessa to the Penine Hills as Stroop and his allies are engaged to trace a missing glass maker, recover a stolen perspective box, an early form of 3-D image, and solve the odd murder.
Having signed an initial two book deal with Headline, Stroop's future is dependent on how well "Guardians" and its sequel are received. In the meantime, Clio has also been working on a stand alone novel while keeping up the day job at the local library in Tain, where she now finds herself placing her own book on the shelves or stamping it out for her customers.
"It's very strange," she admits. "Originally I was going to use a pseudonym, but I decided against it. We have got a few copies, but they are all out at the minute. Because I work in the library, people know me and are curious about the book."
Hopefully they will not be the only ones enjoying Clio's work.
"Guardians of the Key" by Clio Gray is published by Headline, price £6.99