When Biggles hears that Von Stahlein's gang have kidnapped Bertie and Ginger, he is furious. The fact that Zoratov, the leader of the crooks, released the captives makes no difference. Biggles is determined to even the score. He recognizes too that the crooks blundering has given him a tremendous advantage. If his enemies can be thrown into jail, he can continue his search for the missing papers unhindered...