A reform-minded but hardheaded chief of police, James Sullivan (James Farley) hasa yen for making enemies of both colleagues and family members, including daughter Diane (Claudia Dell), whose romance with plainclothes detective Dan Burke (Lloyd Hughes) is met with stern disapproval. Sullivan, however, is brutally murdered by a dart laced with curare and the same fate befalls the attending physician (Francis Sayles). Enter noted criminologist Professor David Graham (top-billed Reginald Denny), whose investigation soon points the finger directly at Lieutenant Burke. But is Burke guilty or is someone else behind the killings?

Reginald Denny … Prof. David Graham
Claudia Dell … Diana Sullivan
Lloyd Hughes … Lieut. Dan Burke
Jim Farley … Chief James A. Sullivan (as James Farley)
Barbara Bedford … Kathleen Ryan
Mary Foy … Mary Ryan
John Elliott … Capt. Bill Withers
Francis Sayles … Police Surgeon Kelly
Al St. John … Radio Officer Jones
Henry Roquemore … Dr. McNeil
Lee Prather … Capt. Perkins
Robert Walker… Capt. Jim Phillips
Jack Kenny … Inspector Silverstein