Laurence Bourne III (Tom Hanks) is a spoiled rich, college kid about to graduate Yale. He also is a gambler who has run $28,000 in gambling debt. Wanting to teach him a lesson, Laurence's father (George Plimpton) is unwilling to bail him out this time. To avoid the loan sharks, Laurence convinces his college roommate to let him take his place as a Peace Corps volunteer on a flight headed to the jungles of Thailand. On the way he meets two other eager Americans; the all-American Tom Tuttle from Tacoma (John Candy) and the beautiful and altruistic Beth Wexler (Rita Wilson). They are all assigned to help build a bridge for a small village. However, the bridge is coveted by the U.S. Army, the local Communist insurgents, and the area's drug smugglers. Together with the help of a local villager, At Toon (Gedde Watanabe), they together must fight off opposition and do what is best for the village.