Edinburgh, Yuletide 1743. Seconded back from the wars in Europe to captain the city’s Town Guard, Robert Catto fears his covert mission to assess the strength of the Jacobite threat will force him to confront the past he tries so hard to forget. Christian Rankeillor, known as Kirsty, her surgeon-apothecary father and his apprentice Jamie are committed supporters of the Stuart Cause. Meeting as enemies, Robert and Kirsty are thrown together as allies by the mysterious death of a young prostitute and their desire to help fugitive brother and sister Geordie and Alice Smart. Robert and Kirsty are increasingly drawn to each other. She knows their mutual attraction can go nowhere. He knows his duty demands that he must betray her.