London, 1760, and Lord John Grey - aristocrat, soldier and sometime spy - finds himself in possession of a packet of papers that might as well have come equipped with a fuse, so explosive are their contents.

The documents reveal a damning case of corruption and murder against a British officer, Major Gerald Siverly, and Lord John is compelled by his own honour as a soldier to bring Siverly to justice. But the documents also hint at a larger - and far more dangerous - mystery, a conspiracy to revive the Stuart cause in the bloodiest way possible. For Lord John, this information not only puts his own life in grave peril, but also brings back personal memories he would rather remained undisturbed.

One of the documents is written in Erse, the language spoken by Irishmen and Scottish Highlanders, and a language Lord John became all too familiar with as governor of Ardsmuir Prison when it was full of Jacobite prisoners.

Including a certain Jamie Fraser.

Jamie's and Lord John's paths now seem destined to cross again, as together they find themselves thrown into a world of ancient relics, bloody rivalries and fiendish plots.