Radio Inspector Art Morrison, Co-pilot Pete, Bobby Baker and the old prospector Zeb Abercrombie were quite unprepared for the shock that greeted them when they finally solved the mystery of the disappearing radio room in the Tyler sanatorium. That, and hearing a call from the transport ship which Jack Baker is flying. As we know, Ann Burton is stowed away in the baggage compartment of this ship which carries two of the diamond smuggling ring, and it's from this ship that comes the radio message that the plane is being forced to seek a landing place because of smoke coming from the baggage compartment...