The rugged landscape of Sequoia National Park is a challenge on the best of days - but when a park ranger discovers an abandoned exclusive campsite with an empty tent and high-end technical gear scattered on the shores of an alpine lake, the wilderness takes on a sinister new hue.

Thirty-two-year-old Felicity Harland - a former FBI agent who left the service in the wake of a personal tragedy and has taken her skills off the grid - is brought in as chief investigator. As a federal agent with the Investigative Services Bureau, she tackles crimes that occur on National Parks lands: unexplained falls, domestic disputes, and now a possible murder case.

The private company that set up the exclusive camp won’t reveal their client list, leaving Felicity with zero clues. As she struggles to find a lead, she’s also haunted by a painful past that dogs her at every step. But when she meets Ferdinand Huxley, a Navy SEAL turned park ranger, she begins to see the value in not just working with a partner but trusting one, too.

The investigation takes Felicity and Hux deep into a wilderness that tests their physical limits to the extreme - and to the mean streets of Los Angeles, where they begin to learn the grisly truth behind the campers’ disappearance....