Payne Harrison, the author of the best-selling Storming Intrepid and Thunder of Erebus, spins his narrative magic vet again -- this time exploring the fascinating but clandestine world of codebreaking and signals intelligence.

Secluded in the quiet Gloucestershire township of Cheltenham is the hypersecret codebreaking and signals intelligence enclave of the British spy machine. Known as Government Communications Headquarters, it is home to a small army of eavesdroppers, linguists, and codebreakers who secretly probe the airwaves for the defense of the realm.

Within this high-tech fortress is a man of great mystery, urbanity, and elan, whose powers in the field of cryptanalysis are nothing short of legendary. His name is Faisal Shaikh, and when an unusual encrypted message crosses his desk, it is like a siren's song to his codebreaking skills. Calling upon all of his knowledge and intuition, Faisal finally unlocks its secrets, and thereby casts himself as a man who knows too much in the eyes of a powerful, mysterious clique at the highest levels of the British government.

To find the key to the possibly unbreakable Black Cipher messages, Faisal Shaikh embarks upon a global quest -- from Japan to Australia, from Fort Meade to Belfast. His only hope is to tear away the veil that conceals a menacing, invisible government lurking within the halls of Westminster before his time -- and his luck -- run out.