It is 1940. Guernsey has been bombed, and is now occupied, by the Germans. A year earlier, young, naïve and recently married Helene, waved goodbye to her husband, who enlisted in the British army. Protected only by her father and Nanna, Helene must carve out a life on the island for the length of the war. Forty years later, her daughter Roz begins a search for the truth about her father's identity and stumbles into the secret history of her mother's life. As Roz discovers, the truth is hard to pin down, and living with the enemy is a messy business.