Biggles and co.
Johns W.E.
Penguin Books
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.