Jack Arno aka Frank Miller as he is known as is a thief and a con man who gets involved and promises marriage to lonely women in order steal from the companies they work for. When one of his victims, a woman named Laura confront him, he pushes her off the roof of a building and stages it as suicide. Laura's sister is not convinced and hires Barnaby Jones to investigate. However another woman named Sheila knows the truth about Frank. Sheila tries to blackmail him with cutting her in on his robberies and marrying her, he murders her too. Now Barnaby is investigating two murders and locating Jack/Frank, trying to prove he is guilty of of both.
—charmardee-smith