The courtroom testimony of George Radcliffe, an American businessman working in London, is so persuasive that a coworker, Donald Heath, is convicted of robbing and murdering the owner of the trucking firm where they were both employed. Although no trace of the money is found, Heath is senteced to life imprisonment. Immediately after the trial, George tells his wife, Martha, that he has made a "killing" in the stock market and is using his new wealth to join Morris Brooke in buying a shipping concern. The venture proves to be enormously successful and within 5 years George has become extremely wealthy. Then a blackmail note arrives in which a disbarred attorney, Jeremy Clay, accused George of having himself committed the murder. Recalling the vagueness of the circumstances under which George acquired his money, Martha begins to doubt her husband and hoping for reassurance, begins her own investigation in to her husband's affairs.