Virginia, 1943: World War II is raging in Europe and on the Pacific front when Kit Sutherland is recruited to help the war effort as a codebreaker at Arlington Hall, a former girls' college now serving as the site of a secret US Signal Intelligence facility. But Kit is soon involved in another kind of fight: government girls are being brutally murdered in Washington DC, and when Kit stumbles onto a bloody homicide scene, she is drawn into the hunt for the killer.

To find the man responsible for the gruesome murders and bring him to justice, Kit joins forces with other female codebreakers at Arlington Hall--gossip queen Dottie Crockford, sharp-tongued intelligence maven Moya Kershaw, and cleverly resourceful Violet DuLac from the segregated codebreaking unit. But as the girls begin to work together and develop friendships--and romance--that they never expected, two things begin to come clear: the murderer they're hunting is closing in on them...and Kit is hiding a dangerous secret.