Biggles and the team are invited to join Scotland Yard as Air Policeman. They set out to track down why robberies are occuring in mid-flight, costing the country millions.

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Air Commodore Raymond approaches Biggles, Algy, Ginger and Bertie with an interesting proposition. Now that the Second World War had ended, he could use good pilots in a new force he is forming as Assistant Commissioner at Scotland Yard. This force would be used to combat flying crooks.

The formation of a force would take some time, and there was a pressing matter to deal with and that is where our heroes come in. Biggles would be offered the rank of Detective-Sergeant.

Raymond informs Biggles of a spate of air related robberies involving the taking of various jewels. Biggles and the gang agree to take the job.