Frank Hardy
Tiger Van Dorn
Ralph Marshall
Valerie Shields
Dorothy Elliott
Tom Banning
Lightning
Chiang-Houseboy
Jim Murphy
Inspector Starrett
Robert Banning
Armand Roget
John Charles
Paul Marshall
Campbell
Professor
Mrs. Maitland
Chandler Elliott
Doctor Coleman
Singapore Joe
Joe Nolan
Angus MacLeod
Hardy's Assistant
Henchman
Greenway
Jackson
Roget Clerk #1
Sailor
Undercover Detective at Dive
Detective Interrogating Pete
Peters
