Separated from friends and family and haunted by personal demons, park ranger Anna Pigeon finds solace in the quiet ruins of the Anasazi civilization of Colorado's Mesa Verde. But the rugged beauty of the park and the mystery of the Anasazi are cruelly overshadowed by danger and death. Lately, visitors to Mesa Verde have been bringing home more than photos…they're also carrying a strange—and deadly—disease. In order to prevent more deaths, Anna Pigeon must find the very human source of an evil wind.