When Margo Roth Spiegelman beckons Quentin Jacobsen in the middle of the night - dressed like a ninja and plotting an ingenious campaign of revenge - he follows her. Margo's always planned extravagantly, and, until now, she's always planned solo. After a lifetime of loving Margo from afar, things are finally looking up for Q... until day breaks and she has vanished. Always an enigma, Margo has now become a mystery. But there are clues. And they're for Q. Printz Medalist John Green returns with the trademark brilliant wit and heart-stopping emotional honesty that have inspired a new generation of readers.