And so that was exactly what he’d done. Fired by a combination of his ancestral pride and his hatred of his peers, one of his first acts after graduating from Cambridge with his first-class degree was to change his name by deed poll from Peter Charles Johnson to Charles Stuart. His second action was to found the stock brokerage company that would, within just a few short years, make him super-wealthy.

The newborn Charles Stuart was relentlessly ambitious and worked eighteen hours a day. He’d made his first million while still in his twenties. By the age of thirty-five he was the owner of one of Scotland’s best private art collections. By thirty-eight he’d bought his first aircraft, built a stable full of racehorses, purchased the villa in the Bahamas as a holiday residence and the chateau in Brittany – from where his beloved, now sadly deceased, mother had told him the Stuarts had originated. Then on his fortieth birthday he’d lavished a multi-million-pound fortune on buying the two-thousand-acre estate in Scotland and started building his dream castle.

The castle was Charles Stuart’s pride and joy and was still, in many ways, a work in progress. He had designed the place to be as historically authentic as possible, albeit with all the trappings of modernity cleverly concealed behind its thick stone walls. One of his nods to authenticity was the underground chamber he’d had built deep inside his fortress’s foundations. He had passed it off to the architects as a wine cellar, but it contained no wine and was in fact a dungeon, modelled on real-life examples from the historic castles of Edinburgh, Loch Leven and, grimmest of them all, the bottle dungeon of St Andrews, a seven-metre-deep hole cut into solid rock and from which there could be no escape.

Stuart had been morbidly fascinated by dungeons ever since reading Walter Scott’s Ivanhoe as a boy. In fourteenth-century France these dark and dreadful pits of incarceration had been called oubliettes: in translation, a place where the hapless prisoner would be left to rot and be forgotten. The delicious sadism of it still sent a shiver down Stuart’s back. He’d often fantasised about hurling his enemies into his very own dungeon and throwing away the key.

And so, the dark, dank pit beneath the castle was where Boonzie McCulloch was to remain a prisoner until he told them what he knew, which would also be the day he died.

Then, or so Charles Stuart hoped, he would be on track to reclaim the one thing he so badly wanted and money couldn’t buy.

The lost treasure of his ancestor. The remainder of the legendary Jacobite gold that Stuart now knew for certain was buried somewhere beneath the ancient pine forest of Loch Ardaich.

Chapter 30