In this long-awaited fourth adventure, Mitch Blaine and his steadfast companion Beyer find themselves facing their most formidable and dangerous enemies yet as they return to the skies. The story begins with Blaine and Beyer enjoying a well-deserved rest aboard their beloved PBY flying boat, the Wayward Wind, recuperating from their latest harrowing encounter with forces of evil.

Their peaceful respite is abruptly interrupted when Blaine receives a distress call from Neil O'Malley, and old friend from his air force days. O'Malley now serves as the Chief Pilot for Paspaley Aviation, the airborne arm of Paspaley Pearls - the largest cultured pearl company in Australia, renowned world-wide for its exceptional and highly valluable pearlls. O'Malley is in a state of desperation: one of Paspaley's historic Grumman Mallards, used to service the remote pearl farms, has vanished without a trace - crew, cargo, and all!

He pleads with Blaine and Beyer to fly to Paspaley headquarters in Darwin, on the remote northwestern coast of Australia's Northern Territory, to help unravel the mystery behind the vanished Mallard and its crew. Accepting the challenge, Blaine and Beyer are drawn into their most perilous adventure yet.