Why is Seymour of Scotland Yard summoned to somewhere so exotic as North Africa? Isn't the death of a Frenchman there something for the local police? Well, yes and no. The local police are answerable to the International Committee, of which the chairman is the British Consul. So naturally the ensuing investigation has to be above board. And so Seymour is bought in as he has had experience of this sort of thing before. And if he fails - well he is expendable, after all...