'Now Listen, Bigglesworth; I'll tell you what I'm prepared to do, and you can please yourself what you do about it. Run this gang of crooks to earth, or point out to me the man that is at the head of it - or the chief operator in this country - and I'll make you a present of a cheque for ten thousand pounds.'Colonel Raymond from Intelligence persuades Biggles, Algy and Ginger to take on the challenge of transporting gold bullion and diamonds to France. Every other firm which has taken the job has failed and the gold has been stolen, the planes crashed or disappeared and the pilots have lost their lives. Biggles comes up with daring scheme after daring scheme, but then Algy is captured and held to ransom and Biggles finds that he's up against his old enemy - Von Stalhein