Brass Bancroft and his sidekick Gabby Watters are recruited onto the secret service and go undercover to crack a ruthless gang that smuggles illegal aliens.

In a Scottish sanitarium, a brilliant research psychiatrist works on a treatment for dementia praecox. He falls for his altruistic female lab assistant and they begin a passionate, tragic relationship.

When Barry Corvall discovers that his new bride is a possible enemy agent, he resigns from the diplomatic service to go undercover to route out an espionage ring planning to destroy American industrial capability.