Valuable electronic parts containing platinum are being stolen from shipments made by Stanwide Mining Equipment Company's cargo planes, and Frank and Joe Hardy are called upon to assist their world-renowned detective father in solving the case.

Mysterious flare -- Factory detectives -- Ghost Pilot -- Police orders -- Warehouse crash -- Aerial mission -- Strange request -- Masked attacker -- Alley escape -- Startling discoveries -- Questionable friend -- Cave clue -- Tornado -- Amazing camouflage -- Capture -- Telltale Initials -- Revealing list -- Air-chart secret -- Hideout trap -- Runway victory.