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.

Elderly schoolteacher Nora Trinell, waiting to meet presidential nominee Dewey Roberts, recalls him as her student back in 1916 and his relation to Dan Hopkins, the man she married and lost.

When Edward Creighton leads the construction of the Western Union to unite East with West, he hires a Western reformed outlaw and a tenderfoot Eastern surveyor.

US-to-Central-America freight service pilot gets engaged to radio broadcaster and promises to take a desk job but the urge for adventure is too strong.

Alice Faye plays the title role in this 1940 film biography of the early-20th-century stage star.