From the #1 bestselling author of Turtles All the Way Down and The Fault in Our Stars Winner of the Edgar Award for Best Young Adult Mystery #1 New York Times Bestseller USA Today Bestseller Publishers Weekly Bestseller Now a major motion picture 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.