Three Couriers

Round about the second anniversary of the start of World War 1, Roger Waterlow is still stuck ashore in charge of the ramshackle British naval intelligence effort in a sweltering notionally 'neutral' country in South-eastern Europe. As rumour follows rumour and the situation becomes daily more confused, Waterlow and his organisation learn of three couriers trying to carry correspondence to Berlin-correspondence that might give the Entente powers vital insights into German intentions for the region, if only they can be intercepted and their papers seized...