"Greenmantle" continues the thrilling adventures of Richard Hannay from convalescence following the Battle of Loos, back to London for a vital meeting at the Foreign Office and thence on a top-secret mission across war-torn German-occupied Europe. His mission; to neutralise and destroy a cunning and potentially devastating German plot to foment Holy War in the Islamic Near East, which could ignite a powder-keg and shake the balance of world power...