How to Be Lost — Amanda Eyre Ward

Joseph and Isabelle Winters seem to have it all: a grand home in Holt, New York, a trio of radiant daughters, and a sense that they are safe in their affluent corner of America. But when five-year-old Ellie disappears, the fault lines within the family are exposed: Joseph, once a successful businessman, succumbs to his demons; Isabelle retreats into memories of her debutante days in Savannah; and Ellie's bereft sisters grow apart--Madeline reluctantly stays home, while Caroline runs away.

Fifteen years later, Caroline, now a New Orleans cocktail waitress, sees a photograph of a woman in a magazine. Convinced that it is Ellie, all grown up, Caroline embarks on a search for her missing sister. Armed with copies of the photo, an amateur detective guide, and a cooler of Dixie beer, Caroline travels through the New Mexico desert, the mountains of Colorado, and the smoky underworld of Montana, determined to salvage her broken family.