Mandrake and his team attempt to prevent "The Wasp" from stealing and using a new Radium invention.
Warren Hull
Mandrake the Magician
Doris Weston
Betty Houston
Al Kikume
Lothar
Rex Downing
Tommy Houston
Edward Earle
Dr. Andre Bennett
Forbes Murray
Professor Houston
Kenneth MacDonald
James Webster
Don Beddoe
Frank Raymond
Dick Curtis
Dorgan
John Tyrrell
Dirk
Stanley Brown
Green
Beatrice Curtis
Rest Home Nurse
Robert Sterling
Henchman
Sam Ash
George Regan
Lester Dorr
Gray
Ernie Adams
Brown
Eddie Fetherston
Rest Home Henchman
Eddie Foster
Ed
Knox Manning
Narrator
Ernie Alexander
Cabbie
Harry Bernard
Construction Camp Watchman
Stanley Blystone
Henchman CX12
Buel Bryant
Rest Home & Ironworks Henchman
Budd Buster
Construction Camp Henchman
George Chesebro
Baker
Charles Dorety
Mill River Inn Henchman
Jerry Frank
Harper Drive Henchman
Kit Guard
Powerhouse Henchman
Frank Hagney
Harris
Chuck Hamilton
Bank Henchman
Eddie Hart
Williams
Oscar 'Dutch' Hendrian
Jerry Jerome
Ward
Eddie Laughton
Kidnapping Henchman
Tom London
Stanley Mack
Roadster Henchman
Pat McKee
Dam Henchman
Charles McMurphy
Construction Foreman
Frank Mills
Gas Station Hitman
Art Mix
Ironworks Henchman
Eddie Parker
Ralph Peters
Mohawk Steward-Henchman
Rose Plumer
Ship Passenger
Cyril Ring
Magic Mart Henchman
Cy Schindell
Charles Sherlock
Ship Henchman
Reginald Simpson
Parsons
Tom Steele
Charles Sullivan
Henchman-Driver
Harry Tenbrook
Streeter
George Turner
Apartment-Raider
Frank Wayne
Blackie Whiteford
Bud Wolfe
Tower Henchman
Bert Young
Steve Clark
Henchman (uncredited)
