The Dow Hour of Great Mysteries is a 1960 series of seven television specials hosted by Joseph Nye Welch.

New York Assistant District Attorney Howard Malloy launches an investigation into a series of murders related to a neo-fascist organisation.

Helen Lester is in love with a man she has known just 24 hours, a playboy who spent time in jail for passing bad checks. Though the man has promised to change, most of her strait-laced relatives are up in arms. But Clare Lester, Helen's grandmother, says the girl is free to join the man she loves. On one condition, that she listen to the story of a day in Clare's own life and of a man she tried to change.