It's 1942. The Nazi war machine appears invincible. Britain is struggling against mounting odds.
In the sky over Wiltshire an unmarked light aircraft is struggling to return to base, but it has no connection with the intelligence operations which are engaged locally in apprehending a Nazi spy, or with Britain's secret underground army, ready to resist any German invasion. And yet, in this rural corner of the English countryside, a sequence of events takes place on which Britain's very survival could depend.
Against the backdrop of preparations for an allied invasion of occupied Europe and covert operations behind enemy lines, a small village is about to be the unlikely setting for Operation Wansdyke and the fight for the recovery of intelligence which could impact on the country's security and possibly on the outcome of the war itself.