Annette Collier's, an industrialist's daughter, anticipated flying lesson with Cass Garrett becomes a kidnapping-extortion nightmare when one of her father's employees hijacks the airplane. The only clue to the whereabouts of Cass's hijacked plane is a jumbled radio message Stan (Todd Susman) believes is in code. The abductors are demanding US$600.000 from her father, Herbert Collier.

Half a dozen fishing trips Cass, Stan and an advertising man have taken to a mountain lake prove to be the cover for an espionage plot that endangers the pilots' lives and threatens to blow up a top-secret experimental fuel plant.