Three years into the Great War, England's greatest asset is their intelligence network--field agents risking their lives to gather information, and codebreakers able to crack German telegrams for hints of the enemy's plans. Margot De Wilde thrives in the environment of the secretive Room 40, where she spends her days deciphering intercepted messages. But when her world is turned upside down by an unexpected loss, she discovers for the first time in her life that numbers aren't enough.