As a young British agent sits in a cell in France, she undertakes to write a log of her experiences under the guise of giving information to the Nazis to avoid torture. Her Gestapo torturer, a fan of literature, appreciates her novelistic approach and allows her to write down the tale of her relationship with her best friend, a pilot named Maddie, and the circumstances that led to the two flying to France and being shot down.This story is haunting, heartwrenching, and oddly beautiful. It's also very gruesome. "Verity" describes her tortures and those of her fellow inmates matter-of-factly, while the reader shudders in sympathy. I found myself searching frantically for glimpses of humanity in Verity's captors, and was unsure whether to be relieved or even more disturbed when the characters' humanity manifested itself in myriad small ways. I think I ended up on the side of "even more disturbed." But I always say I want villains who are real people with real, human motivations and are all the more scary for it. Those are defintiely present here.Minor spoilers:Verity's unreliability as a narrator becomes clear fairly early on, and we spot hints of subterfuge (but from whom and for whom?) in underlined passages. But the surprises just keep coming, and it's not until late in the book that Verity's true genius is revealed.Some larger spoilers:What this book is not is a book with a happy ending, and that's why for me, this was only a four star read. If this book had ended with Maddie successfully rescuing her friend from the clutches of evil and riding off into the sunset in a plane with the flames of the exploded Gestapo building rising in the background, this would have been a five star read. I understand why Wein chose this route, and I'm not saying it was the wrong choice. I'm just saying that for me, personally, a happy ending is always preferable. It's one of the reasons I read YA and fantasy--happy endings are par for the course. This book is depressing.Overall, this book is disturbing and occasionally confusing (all is revealed in the end), but well worth the read nevertheless.