It is November 1915, the midst of World War I, and Richard Hannay and his friend Sandy are convalescing from wounds received at the Battle of Loos. Hannay is summoned to the Foreign Office by Sir Walter Bullivan. It appears German and Turkish allies are plotting to throw the Middle East, India and North Africa into turmoil. Hannay undertakes a perilous journey through enemy territory to Constantinople. Once there, he must thwart the Germans' plans to use religion to help them win the war.