The Conversation delves into the world of private security and privacy issues. Harry Caul is a securities expert who is hired by the Director to tape a private conversation in the middle of a busy square. Harry successfully tapes the conversation but is terrified when he believes that the Director plans to kill the young couple. Since the Director isn't available, Harry refuses to turn over the tapes, and this begins a new series of events.

Harry finds that he is being followed by Martin Stett, a man working for the Director. Finally, they send a woman to seduce Harry and steal the tapes. Afterward, Harry tries to confront the Director and even goes to a hotel to try to stop the murders he believes will happen. Finally, Harry discovers the truth behind the conversation, and he is warned by Martin that they will be watching him. Harry...