In order to win back his girlfriend, Mike Shayne promises to give up his detective practice and get a job as riveter in an aircraft plant. He quickly finds himself investigating the theft of industrial diamonds from the plant's safe and, utilizing a variety of false identities, traces them first to a dress factory and later to a Hawaii-bound ocean liner. Escaping several attempts on his life, he is able to uncover a Nazi smuggling ring, but the location of the missing diamonds continues to elude him.
Lloyd Nolan
Mary Beth Hughes
George Reeves
Helene Reynolds
Steven Geray
Henry Victor
Curt Bois
Marie Blake
Emmett Vogan
Mae Marsh
Frank Orth
Ivan Lebedeff
Wade Boteler
Charles Trowbridge
Edward Earle
Cliff Clark
Arthur Loft
Ann Doran
Charles Williams
Monica Bannister
Ray Beltram
Ruth Clifford
Bud Geary
Mary Gordon
Al Kikume
Bert Moorhouse
Barry Norton
Harry Carter
Don Dillaway
Lester Dorr
Mildred Gover
Gerardo Sei Groves
Nora Lane
Perc Launders
George Melford
Paul Michael
Steve O'Brien
Pat O'Malley
Addison Richards
Cyril Ring
Rudy Robles
Tim Ryan
Walter Sande
Edwin Stanley
Jack Stoney
Charles Tannen
Hans von Morhart
Basil Walker