Outside, the rain is beating a relentless riff that is familiar to anyone who has lived through a monsoon in Southeast Asia. Inside the Army-issue tent in a clearing at the jungle's edge, Nash A. Miller, a onetime helicopter door gunner and crew chief, is changing into a dry pair of camouflage fatigues. As his two watchdogs prowl silently, Miller, nicknamed "Nam" (his initials), recounts his tale with a small, innocent smile. It begins at a firebase in the badlands west of Kontum, near the Vietnam-Cambodia border, in the summer of 1970.
As Miller's gunship, a ponderous Huey "hog," was taking...