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—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. Only then could she begin the perilous work of helping free her homeland—France—from the German occupier.