In the middle of the First World War, and sweltering in the heat of a nominally neutral country in South-eastern Europe, disillusioned Naval Intelligence officer Roger Waterlow seeks to make sense of scraps of information gathered by his agents, in the face of indifference or outright hostility from most of his colleagues at the British Legation. But when word reaches him that a German officer visiting from Berlin for talks with the country’s pro-German king is to be picked up by submarine, violating the country’s ‘neutrality’, he sees the chance to finally make a real difference in the war…