In this long overdue fourth installment, Mitch Blaine and his amiable, ever-present sidekick Beyer, take on their most evil and dangerous adversaries thus far in their incredible aerial adventures. Relaxing in customary and inimitable style on their PBY flying boat the Wayward Wind while recovering from their latest dealings with the ungodly, Blaine gets a phone call from an old Air Force mate. Neil O'Malley is now the Chief Pilot for Paspaley Aviation. Paspaley is the largest cultured pearl company in Australia and is world-renowned for it superb, and very expensive pearls. O'Malley is desperate! One of his Grumman Mallards-the historic flying boats Paspaley use to service their pearl farms-has gone missing; crew, cargo and all. Only problem is, the 'cargo' on board this flight is the precious annual pearl harvest-a magnificent collection of thousands of exquisite pearls with a street value of millions of dollars! Neil is convinced that the pilots could not possibly have been guilty of conspiring to steal the loot, but it appears there is no other logical explanation. He entreats Blaine and Beyer to join him at Paspaley's headquarters in Darwin up on the far northwest coast of the Northern Territory, to see if they can help solve the mystery of the missing Mallard and its crew. And in so doing, he plunges our reluctant duo into their most gut-wrenching adventure yet. This time, they must deal with everything from wild, rugged, isolated Outback terrain and water inhabited by some of the deadliest creatures on the planet to Indonesian pirates out to steal the priceless hoard for themselves.