With his trademark brilliant wit and heart-stopping emotional honesty, the Printz Medal-winning author of Looking for Alaska returns with a novel about a teenage girl who has mysteriously vanished, and the boy who looks for her by following the clues she left behind just for him. High school senior Quentin Jacobsen has spent a lifetime loving the magnificently adventurous Margo Roth Spiegelman from afar. So when she cracks open a window and climbs back into his life, dressed like a ninja and summoning him for an ingenious campaign of revenge, he follows. After their all-nighter ends and a new day breaks, Q arrives at school to discover that Margo, always an enigma, has now become a mystery. But Q soon learns that there are clues, and they're for him. Urged down a disconnected path, the closer he gets, the less Q sees of the girl he thought he knew.