Major Waring (Leon Ames) of the Cipher Bureau is hunting for enemy spies by breaking their codes. After his success, the spy cell change their code. Waring's younger brother Paul (Don Dillaway) is called into help but is unwittingly caught in a honey trap by the beautiful female agent Therese Brahm (Joan Woodbury).
Paul is targeted by the enemy and loses top secret US Navy plans. Waring, assisted by Helen Lane (Charlotte Wynters), has to break the enemy codes, retrieve the plans and save his brother's career...
The film can be a bit slow moving at times but is well structured. The cracking of the codes is shown in detail and that is probably the most interesting part of the film, and the use of a music notation typewriter!
Panama Patrol is the sequel to this film.
