The story takes place in Brittany in 1944, a few weeks before the Allied landings in Normandy. Blanche Lacassagne and her daughter-in-law Anne leave Paris to take refuge at their family farm in Kerbriant, a village in southern Morbihan. Once there, they discover that their phone line has been mistakenly connected to the Kommandantur’s line. The Resistance quickly seizes this opportunity to eavesdrop on the German officers’ conversations.