As a guest of his childhood chum Harry Lime, a writer of pulp Westerns, Austria, Holly Martins, arrives penniless in postwar Vienna, only to learn he has expired. Martins develops a conspiracy theory after learning of a"third person" present at the time of Harry's passing, running into disturbance from British officer Important Calloway, also falling headoverheels for Harry's griefstricken enthusiast, Anna.