Once a Runner is the story of Quenton Cassidy, a collegiate runner at fictional Southeastern University whose lifelong dream is to run a four-minute mile. He is less than a second away when the political and cultural turmoil of the Vietnam War era intrudes into the staid recesses of his school's athletic department. After he becomes involved in an athletes' protest, Cassidy is suspended from his track team. Under the tutelage of his friend and mentor, Bruce Denton, a graduate student and former Olympic gold medalist, Cassidy gives up his scholarship, his girlfriend, and possibly his future to withdraw to a monastic retreat in the countryside and begin training for the race of his life: a head-to-head match with the greatest miler in history.