An eccentric and dogmatic inventor sells his house and takes his family to Central America to build a utopia in the middle of the jungle. Conflicts with his family, a local preacher, and with nature are only small obstacles to his obsession. Based on the novel by Paul Theroux.

Big-hearted Chicago family man Chet has brought his family to a lakeside resort area, and although his wife and kids aren't quite as excited as he is, Chet has high hopes for the vacation. However, his optimism is sabotaged when his obnoxious brother-in-law Roman drops in unexpectedly, along with his snooty, strange family. Chet and his family try to stay open-minded, but they find it difficult to relax and enjoy themselves because of the constant annoyance of Roman's presence.