Jamison begins “The Immortal Horizon” by describing a group of men getting ready for a long-distance run through the Frozen Head State Park in Tennessee. When a man sitting in a lawn chair lights a cigarette, the Barkley Marathons starts. Jamison then provides historical context for the marathons, which began with James Earl Ray breaking out of prison and, after 55 hours and eight miles, being caught. Lazarus Lake (Gary Cantrell at birth) visited the terrain and created a marathon so difficult that only eight men have completed it. There is no trail, and the loop passes through briars and water. To be accepted, applicants must complete an abnormal questionnaire, but the run itself is not posted or sponsored by any official source. Jamison’s brother Julian is one of the 35 runners selected for this year’s run, and Jamison is acting as his support system at base camp.

Jamison lists the items deemed vital for completing the run, noting the importance of the compass and batteries. A man named Doc Joe oversees grilling chicken over a fire and is insulted when Jamison asks him about a rumor that the chicken is served blackened on the outside but raw on the inside.