In the Enemy's Shadow — Pam Crooks

The Spyglass Project is the first book of the Secret Six series set in the Prohibition era of 1920s Chicago, featuring Major Michael Malone as an alcoholic ex-military intelligence officer who infiltrates the city's underground to expose a crime lord funding the rise of Adolf Hitler. The book opens with a Prologue set eight years earlier in a prisoner-of-war camp in Wittenberg, Germany, during World War 1.

In the Enemy's Shadow begins where the Prologue in The Spyglass Project ends and is a behind-the-scenes look at the life of double-agent, Hedda Klein, leader of a secret dissident group and working as a spy for the United States government under the code name of Agent Delilah. After she witnesses the murder of a troubled friend and comrade, she must flee to save her own life, only to encounter revenge and betrayal from a woman she trusts most.