Based on the best selling novel by Graham Greene.Thomas Fowler, a British journalist covering the Indo-China war, comes under suspicion when the body of a young American is found floating in the river. Through a series of flashbacks we learn that the young American had come to Vietnam to start a 'third force' to end the war. Fowler, in a fit of jealousy, agrees to act as a 'fingerman' in a communist plot to kill the American when he discovers that the American has fallen in love with his girlfriend.