A soldier named Cacciato walks away from the Vietnam War, heading west toward Paris. His squad is ordered to follow him. The novel weaves between three time-streams: the observation post where Paul Berlin sits on watch, the actual past of the war, and the fantasy of following Cacciato from Vietnam to Paris.
John Wade, a Vietnam veteran and politician, retreats to a lakeside cabin after a catastrophic election defeat. Then his wife Kathy disappears. The novel assembles evidence — testimonies, documents, O'Brien's own speculations — without ever resolving what happened.