The year is 1943. The setting locations are England, and Nazi-occupied France. 
 The book is told in a split first-person point of view (which occurs halfway through the book), between Queenie ("Verity"), and her best friend, Maddie. Queenie is a bold, German-speaking Scottish aristocrat who has been captured by the Nazis, and is being interrogated as a spy. Maddie is more of a simple country girl with a knack for mechanics, who's managed to work her way into piloting for the British ATA (Air Transport Auxiliary). She also happened to be responsible for dropping Queenie off for her ill-fated mission... 
 To her credit, the author went to a great deal of trouble to ensure nearly all the details she presents were at least historically possible, however technically fictionalized. The writing is strong and deftly skilled--fraught with a thoughtful profundity and emotional resonance the likes of which I rarely see in YA lit. Indeed, I often forgot that YA was the intended audience. 
 The POV switch in part 2 is actually a pleasant surprise. It was getting a bit straining to continuously be in the midst of Verity's physical and mental torture. While surprisingly non-graphic, the implied was more than enough to maintain a disquieting amount of tension. And the compromised humiliation she is reduced to will leave readers continually wondering: "What would I do if I were in her?" 
 The complexity of characterization, even in the Nazis, is admirable. The only thing I found myself struggling with was relational. I wasn't entirely convinced of how thoroughly bonded Maddie and Verity are in their friendship. The loyalty was understandable--if only because of the unifying factor of wartime pressures, and being very young and female in the midst of a massively male-dominated work/war-force. But the friendship itself didn't quite get into the emotional depth I was hoping for. The pacing also lagged a bit through the first part of the story, as Verity/Queenie had more than enough reason to stall in what she gave up to the Gestapo. 
 Regardless of my minor qualms, I wanted to reiterate how uniquely compelling I found this work. It's an immersive history lesson and an ethical quandary, wrapped in a remarkable storytelling effort. Even if you think you've had about enough of the war against Nazi occupation, this one is well worth your time.