One semester before graduation, Danielle Caruthers, a Yale senior, takes a train to New York City and vanishes. No one has heard from her since-not her parents in gilded Westport, not her senior advisor, eminent art historian Whitmore Verhaast, and not her roommate, Sabrina Gutierrez. The daughter of a single Colombian mother, Sabrina grew up on the rough side of Chicago and has been defying the odds ever since-most recently with a full scholarship...