The Missionary and the Marine is a Christian romance set in Naples, Italy, during the winter of 1971 and spring of 1972, between a missionary girl named Maddie Gallagher, and Nathan Kessler, a US Marine, stationed at the Marine Barracks, which guards the NATO base and other international facilities. The girl lives with her mother, father, and little brother in the Way Station, in downtown Naples, a homey place where American servicemen and women from all branches of the military may come for a home-cooked meal, participate in a Bible study led by a former Navy chaplain, read books and magazines, or play ping pong, foosball, or play musical instruments, or simply fellowship with one another. Nathan Kessler is resistant to Maddie's efforts to lead him to Christ because of something that happened in his past, an event that he keeps very close to the vest. even so, a love between the two grows and blossoms in spite of the fact that they are "unequally yoked", a fact that deeply disturbs Maddie's heart and weighs upon her despite her prayers for the man she loves. To complicate matters further, Nathan meets a beautiful Roman girl named Nicoletta, and their explosive love affair takes them from the Roccaraso ski resort, to Rome, and finally to the exotic island of Ischia in the Bay of Naples, where he learns a truth that changes his life.