March 1975. Twenty-one-year-old Mark Hanson set out with friends on a spring break hike from Davenport Gap into the Great Smoky Mountains. By afternoon, a sudden storm swept across the ridges — sleet, snow, plunging temperatures. The group split, with Mark and one friend pushing toward Tri-Corner Knob shelter. In the darkness, just yards from safety, Mark collapsed. When morning came, he was gone. Days later, search teams found his body three miles away in rugged backcountry. This episode retraces his last known movements and the mystery of what happened after he disappeared into the storm.