In 1943, two British intelligence officers concoct Operation Mincemeat, wherein their plan to drop a corpse with false papers off the coast of Spain would fool Nazi spies into believing the Allied forces were planning to attack by way of Greece rather than Sicily.

In a dusty post-war summer in rural Warwickshire, a doctor is called to a patient at lonely Hundreds Hall. Home to the Ayres family for over two centuries, the Georgian house is now in decline. But are the Ayreses haunted by something more sinister than a dying way of life?