"Code Name Verity," by Elizabeth Wein I'm in a bit of a predicament. Oh, it's not the predicament of a girl pilot who has crash-landed in occupied France during World War II, or of a girl spy who has been captured by the Gestapo, but it's still problematic. I have to review a book in which even the hint of plot summary could ruin everything. "Code Name Verity," by Elizabeth Wein, is a fiendishly plotted mind game of a novel, the kind you have to read twice. The first time you just devour the story of girl-pilot-and-girl-spy friendship and the thrill of flying a plane and the horrors of Nazi torture and the bravery of French Resistance fighters and you force yourself to slow down, but you don't want to, because you're terrified these beautiful, vibrant characters are doomed. The second time, you read more slowly, proving to yourself that yes, the clues were there all along for you to solve the giant puzzle you weren't even aware was constructed around you, and it takes focus and attention to catch all the little references to the fact that nothing is what you thought. Especially while you're bawling your eyes out. I am a coward. I wanted to be heroic and I pretended I was. I have always been good at pretending. This is how the book opens. Soon we learn our narrator is Queenie, the girl spy. She's Scottish, and she's been caught because she looked the wrong way (left, Britishly) while crossing a French street. She might have talked her way out of trouble - we quickly see she's charming, funny, flirty and has great nails - but for reasons that will become clear, she has no identification papers. She's imprisoned in the Château de Bordeaux, a once elegant hotel in a small city by a river in central France, now serving as a Gestapo headquarters. Captain von Linden, Queenie's captor, forces her to write her confession between bouts of torture carried out by a pale, pinch-mouthed deputy named Anna Engel. For as long as Queenie writes, she will be allowed to stay alive. So Queenie unfurls the story of her friendship with the pilot, Maddie, interspersed with enough information about codes and airports to live for one more day, and another, and another. Commander von Linden, whom she compares to Captain Hook ("in that he is rather an upright sort of gentleman in spite of his being a brute"), is a cultured man who gets wrapped up in Queenie's story. When Fräulein Engel becomes impatient with what she sees as Queenie's pointless literary fancies, von Linden interrupts her. " "Fräulein Engel, you are not a student of literature," he said. The English flight officer has studied the craft of the novel. She is making use of suspense and foreshadowing. . . . Engel dutifully slapped me into silence and said: "She is not writing a novel. She is making a report." " Well, yes and no. Through Queenie's writing - first on creamy hotel stationery, then in increasingly frantic scribbles on prescription forms bearing the name of a Jewish doctor, on sheet music once owned by a Jewish flutist and on recipe cards cadged from the Nazi cook - the reader, too, learns the story of the girls" blossoming friendship. Unlike the aristocratic Queenie, Maddie is a commoner. She's not gorgeous or smooth with men. But she's ethical, fierce and loyal, and we find out as Queenie does that she's a skilled pilot and a genius mechanic. "It's like being in love, discovering your best friend," Queenie writes, and Wein conveys that love gorgeously. "We're still alive and we make a sensational team," Queenie says. And they do. This is a rare young adult novel entirely about female power and female friendship, with only the faintest whiff of cute-boy romance. I'd tell you more about the "Usual Suspects"-meets-"If on a Winter's Night a Traveler" plot, but then I'd have to kill you. I do think "Code Name Verity" will appeal more to adults than to teenagers. The cover is unfortunately off-putting (with its stark image of two girls" wrists bound together with twine, it looks like a lesbian version of "Fifty Shades of Grey"); the torture scenes are fairly graphic, and the period detail is dense. I could have done with a little less information about vintage airplanes and ballpoint pens (though an author's note indicates that some bits that seem far-fetched are based in reality). I doubt most teenagers will get the references to "A Thousand and One Nights," Rudyard Kipling's "Kim" and the death of Admiral Hardy, all of which make the book challenging in a lovely, bookish way. (Wein's earlier novels are set in Arthurian Britain and sixth-century Ethiopia. She has a doctorate in folklore and a pilot's license. She met her husband at a dinner dance for hobbyist bell ringers. Nerd.) But every reader will get the "Peter Pan" references, and they're what's most important. A smart book about the power of female friendship is like finding Neverland. Marjorie Ingall is a columnist for Tablet magazine.