The Duke's Gambit is the fifteenth installment in Tracy Grant's Malcolm & Suzanne Rannoch historical mystery series!
Former spies Malcolm and Mélanie Suzanne Rannoch return to Dunmykel Castle in Scotland in response to a secret summons from Malcolm's grandfather, the Duke of Strathdon. The duke has a plan that will allow the Rannochs to resume their former life in Britain. Malcolm, worried that Mélanie could face treason charges for her past as a French spy, wants nothing more than to take his family safely back to Italy. But when Malcolm's sister Gisèle disappears from Dunmykel, Malcolm instead find himself doing the one thing he didn't want to do—risking a return to London in search of his missing sister.
Meanwhile in Scotland, Mélanie uncovers information that connects her own shadowy past with Gisèle's disappearance, which sends Mélanie off on a quest of her own. As they unravel the tangled threads, Malcolm and Mélanie learn Gisèle's disappearance is part of a dangerous game involving two old enemies and the highest reaches of Britain's government. The stakes rise still higher when one of their enemies is arrested for murder. From snowy Scotland to glittering Mayfair drawing rooms and the stews of St. Giles, the Rannochs unearth a conspiracy that could topple kings—and shake their family to the core.