Hoping to avoid gambling debts, rich playboy Lawrence Bourne (Tom Hanks) stows away on a plane of Peace Corps volunteers set for Thailand. Once aboard, he meets the outrageously affable Tom Tuttle (John Candy), who shows him the ropes. After landing, the crew is stationed in a small town where they are to construct a bridge. Along with the lovely and altruistic Beth Wexler (Rita Wilson), the group begins work, but soon discover the CIA, communists and a drug lord are eyeing the bridge.