A Flag for Sunrise is about Catholics—a nun, a priest, an anthropologist, a drifter—caught up among spies, gun runners, murderers, maniacs, and revolutionaries in a poor Central American country ruled by American business interests and the CIA through a local military regime. The plot is complicated and built upon short scenes, some of them so intensely dramatic they could be published independently. What holds them together is suspenseful action, an atmosphere of neurasthenic menace, and Stone's prose style. Lean, tough, quick, and smart, it is perfect for violent action, yet lyrical enough for Stone's nun as she contemplates her own mind, her "inward place."…

The plot has largely to do with a journey taken by three characters: Frank Holliwell, a professor of anthropology who worked for the CIA in Vietnam; a beautiful nun named Justin; and Pablo Tabor, a drifter of uncertain racial origins, who is...