Between the silver ribbon of morning and the green glittering ribbon of sea, the boat touched Harwich and let loose a swarm of folk like flies, among whom the man we must follow was by no means conspicuous-nor wished to be. There was nothing notable about him, except a slight contrast between the holiday gaiety of his clothes and the official gravity of his face. His clothes included a slight, pale grey jacket, a white waistcoat, and a silver straw hat with a grey-blue ribbon. His lean face was dark by contrast, and ended in a curt black beard that looked Spanish and suggested an Elizabethan ruff. He was smoking a cigarette with the seriousness of an idler. There was nothing about him to indicate the fact that the grey jacket covered a loaded revolver, that the white waistcoat covered a police card, or that the straw hat covered one of the most powerful intellects in Europe.