** THE INSTANT NEW YORK TIMES BESTSELLER ** ** AN AMAZON "BEST BOOKS OF THE MONTH" FOR AUGUST 2023 (Biographies & Memoirs) ** As a park ranger with the National Park Service's law enforcement team, Andrea Lankford led search and rescue missions in some of the most beautiful (and dangerous) landscapes across America, from Yosemite to the Grand Canyon. But though she had the support of the agency, Andrea grew frustrated with the service's bureaucratic idiosyncrasies, and left the force after twelve years. Two decades later, however, she stumbles across a mystery that pulls her right back...