It is 1941, and the world is at war. Young Theresa Compton is left devastated after giving up her illegitimate child and joins the Special Operations Executive, an organisation of undercover agents working behind enemy lines. Her mission is to assist a Resistance group run by the handsome Pierre Reuben, and it is not long before they fall in love. Theresa gives birth to Pierre's child, but circumstances soon tear both Pierre and the child from her. In London, 1963, an older Theresa is haunted by her experiences during the war. The past tangles with the present in her damaged mind and Theresa soon feels she has to make a terrifying decision. Her long-lost children are seeking answers. Will Theresa be reunited with them, before it is too late?