The Peruvian Department of the Interior recruits noted archeologist Professor Roger Williams to conduct a dig in the ruins of Machu Picchu. Believing in the potential for exciting discoveries, he invites his old friend Erin Mathews to participate. While flying into Cusco, Erin tells her husband Craig, a retired army intelligence officer and ex-CIA operative that they'll be working at an elevation of 8,000 feet in the Peruvian Andes. The thin air...