During a fierce thunderstorm, Sky picks up a mayday call from a Air Force courier plane which is about to run out of gas. The Air Force request Sky's assistance in locating the downed aircraft because the pilot is transporting secret documents that are of interest to foreign governments. Sky locates the plane wreck, but the pilot is nowhere to be found. When he discovers that the navigational instruments have been tampered with, Sky fears that enemy agents may have located and stolen the secret plans and are headed for the nearby Mexican border.