"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 and the course of the war. Hannay is assisted by three intrepid companions: the suave, dashing, exotic and romantic Sandy Arbuthnot, the American - John Scantlebury Blenkiron, and the South African Boer Scout - Peter Pienaar.