In Europe, the Germans are still totally unaware that the allies have broken the complicated ENIGMA code, whilst in the Far East theatre, where the Japanese are using their own version of the ENIGMA code, an intercepted communication leads Brigadier Donald Reisman, head of British Intelligence in Calcutta, to the damning conclusion that the war's most closely guarded secret is no longer secure. Can he afford to test his theory when, to do so, he must open Pandora's box? And can he afford not to? One way or the other he must act - and quickly Lives are at stake. Future campaigns are at stake. For without the ENIGMA secret the already hard- pressed allied armies are in danger of being swept further and further westward. Reisman's eventual decision leads his team back into Japanese occupied Burma in an effort to free from a prison camp the one man who can answer the burning question.