While serving as an observer with the British Expeditionary Force in 1940, Ian Wylie survives a massacre of prisoners. In its aftermath, he resolves to find a way of sitting out the rest of the war, safe from both the Germans and his responsibilities.At first, he finds sanctuary on a small farm owned by a teacher, Andrea Morel, who harbours him until an incident leaves her no choice but to send Ian away. With no wish to return to England and the war, Ian assumes the identity of Andrea's sister, Diane Lambert, and accepts an offer to teach at a Catholic girls' school in Normandy.His efforts to turn his back on the war are frustrated by a local businessman who enlists Ian's aid in passing intelligence on German activities in Normandy to the Allies as well as by a group of schoolgirls who take it upon themselves to fight for the liberation of France.