Highly respected defense attorney Dwight Bradley Mason (Walter Pidgeon) is able to clear young Rudi Wallchek (Keefe Brasselle) of a murder rap. When it's all over, however, Rudi lets slip a careless comment which leads Mason to believe that his client was guilty after all. Using the evidence at hand, the attorney retraces his steps, only to discover that one of the town's leading citizens is a criminal mastermind. The solution to this ethical dilemma is straight out of the "postman always rings twice" school of crime fiction. Even after justice has been served, however, Mason's conscience dictates that everyone responsible for all previous legal miscarriages be punished -- including himself!