It’s 1944, and the world is at war. While most seventeen-year-old girls in London are running air-raid drills, Betty Sweeney is determined to make a real difference. Lying about her age, Betty joins the Special Operations Executive, a top-secret government agency that trains spies and sends them behind enemy lines. Now known by her secret alias, Adele Blanchard, she finds herself parachuting into Nazi German–occupied France, under the cover of darkness. Joining forces with the underground Resistance movement, Adele must relay crucial messages in anticipation of the Allied invasion on D-Day—and even a small mistake could land her in the hands of the ruthless Gestapo.