During World War II Nathalie “Lily” Sergueiew, a woman of mystery, confidently seduced the German Intelligence Service into employing her as a spy against their British enemy. Little did they know that this striking woman – who turned heads when she walked into a room with her little dog Babs – was playing them and would work with their enemy against them. Her diary chronicles her months-long journey to becoming a double agent for the British under the code name Treasure. From the moment she conceived the idea of becoming a double agent, Lily faced challenges on two fronts: first, she had to convince the Germans to ask her to spy for them; second, she needed the British to believe her story, to take her seriously, and to employ her in the role that she was destined to perform. Only then could she begin the perilous work of helping free her homeland – France – from the German occupier. I Worked Alone: Diary of a Double Agent in World War II Europe tells the story of Lily’s journey to accomplish her challenging goal in her own words.