Londoner Madeleine Grant is studying at the Sorbonne in Paris when she marries charismatic French journalist Giles Martin. As they raise their son, Olivier, they hold on to a tenuous promise for the future. Until the thunder of war sets off alarms in France.

Staying behind to join the resistance, Giles sends Madeleine and Olivier to the relative safety of England, where Madeleine secures a job teaching French at a secondary school. Yet nowhere is safe. After a devastating twist of fate resulting in the loss of her son, Madeleine accepts a request from the ministry to aid in the war effort. Seizing the smallest glimmer of hope of finding Giles alive, she returns to France. If Madeleine can stop just one Nazi, it will be the start of a valiant path of revenge.

Though her perseverance, defiance, and heart will be tested beyond imagining, no risk is too great for a brave wife and mother determined to fight and survive against inconceivable odds.