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 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.