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.

• 20th Century Fox
• Lloyd Nolan
• Mary Beth Hughes
• George Reeves
• Helene Reynolds
• Steven Geray
• Henry Victor
• Curt Bois
• Marie Blake