Holly Martens (Joseph Cotten) receives a job offer from his friend Harry Lime (Orson Welles) in postwar occupied Vienna. He arrives there only to find that Lime is dead and every witness has a different story. Being a pulp writer, Holly thinks he can solve the mystery.
But this is a Graham Greene story, and the mystery is not just a whodunit but an exploration of evil. Tangling with a nihilistic band of black marketers exploiting the corruption and ruin of a great city after the war, Holly is told that he is in way over his head.
The movie has many unusual touches. Expressionist camerawork increases the feeling of dread. The traditional orchestral accompaniment is eliminated, replaced by a single folk musician playing an eerie tune on a zither. Several scenes of the movie are in un-subtitled Austrian-German, leaving the audience feeling as bewildered as Holly as he tries to communicate with the locals. Holly's amateur sleuthing is frequently comic, in a story that is deadly serious.
One of the masterpieces of noir cinema.