First Published on 4th March 1954 - 159 pages

Biggles and the team are sent to investigate the possibility that agents from behind the Iron Curtain are being placed on isolated islands in the world's great Oceans. These islands are still the territories of various countries such as the United Kingdom and France and, although uninhabited, will have great strategic importance as refuelling stations for aircraft as world travel increases. For weeks, they survey islands and find nothing but when they visit the French held Crozets islands in the South Indian Ocean (taking Marcel Brissac with them) they find a castaway. It is this which is depicted on the dust cover of the book. He is Alf Robinson, survivor of a ship called the Kittiwake which sank in a storm. He has an interesting story to tell because he saw a Russian submarine put a German crew member aboard his island. He befriended the German who gave him vital information before he died from ill health. Biggles returns to England to brief Air Commodore Raymond and the rest of the adventure (from page 62 onwards) tells of what happens to Algy, Ginger, Bertie and Marcel while Biggles is away. On a further mission to one of the other islands in the Crozets, Ginger and Marcel are stranded ashore when Algy and Bertie have to leave urgently due to the arrival of the Russian sub. Various problems, not least the weather, prevent Algy and Bertie from returning, and when they do return, from leaving. Biggles arrives in time to see the submarine destroyed.