In 1940, Joseph Mitchell, a New Yorker staff writer, meets Joe Gould, a homeless writer who attended Harvard and cadges contributions to the Joe Gould Fund. Mitchell is fascinated with this Harvard grad and writes a piece about him, bringing Gould some celebrity. Gould tells to Joseph that he is writing a voluminous "Oral History of the World", a record of 20,000 conversations he has overheard on the streets, but he never shows him anything. Mitchell starts doubting about the existence of such work and, Gould's touchy, querulous personality and his frequent dropping in on Mitchell for hours of chat lead to a breakup, but the two stay in touch until Gould's death and Mitchell's unveiling of the secret.