Desperate to discover a cure for the cyclical 48-year-fever, known as Trailmen’s fever, Dr. Randall Forth persuades a colleague, Dr. Jay Allison, to undergo hypnosis. He calls forth a secondary personality, Jason Allison, is gregarious and an experienced mountain climber, while Dr. Jay Allison is a cold, clinical man with no outdoor skills. Jason is asked to lead an expedition into the Hellers to collect medical volunteers from among the Trailmen. Accompanying him are Rafe Scott, Regis Hastur, Kyla Raineach, a Renunciate guide, and several others. During the trip, Jay/Jason yo-yos between his two personalities – one warm and charming, the other distant and clinical. Jason, the warm personality, falls in love with Kyla.
