"Bah! Your fancy--mere fancy!" declared the professor of chemistry. "I know you've been unduly suspicious for a long time, but I tell you that Ella and her lover are far too much absorbed in their own affairs to trouble about our business." Ortmann shrugged his shoulders. He did not tell his friend Drost the true extent of his knowledge, for it was one of his main principles never to confide serious truths to anybody. By that principle he had risen in his Emperor's service to the high and responsible position he now occupied--the director of The Hidden Hand. As such, he commanded the services of many persons of both sexes in the United Kingdom. Some were persons who, having accepted German money or German favours in the pre-war days, were now called upon to dance as puppets of Germany while the Kaiser played the tune. Many of them, subjects of neutral countries, had been perfectly friendly to us, but since the war the relentless thumbscrew of blackmail had been placed upon them by Ernst von Ortmann, and they were compelled to do his bidding and act against the interests of Great Britain. Over the heads of most of them, men and women--especially the latter-- the wily Ortmann and his well-organised staff held documentary evidence of such a damning character that, if handed to the proper quarter, would either have caused their arrest and punishment, or, in the case of the fair sex, cause their social ostracism. Hence Ortmann held his often unwilling agents together with an iron hand which was both unscrupulous and drastic. Woe betide either man or woman who, having accepted Germany's good-will and favours before the war, now dared to refuse to do her dirty work. Truly, the Hidden Hand was that of the "mailed-fist" covered with velvet, full of double cunning and irresistible influence in quite unsuspected quarters. Old Theodore Drost was but a pawn in Germany's dastardly attack upon England, but a very valuable one, from his intimate knowledge of explosives. Moreover, as an inventor of death-dealing devices, he certainly had no equal in Europe. In order to discuss in secret a daring and terrible plot, the pair had lunched in company at Park Lane. At that same hour, on that same day, Flight-Commander Seymour Kennedy, in his naval uniform with the "pilot's wings," was on leave from a certain air-station on the South-East coast, and was seated opposite Ella Drost in the Cafe Royal, in Regent Street, discussing a lobster salad _tete-a-tete_. It was one of the favourite luncheon places of Drost's daughter. The revue in which she had been appearing and in which, by the way, Ortmann was financially interested in secret, had finished its season, and the theatre had closed its doors for the summer. Consequently Ella had taken a tiny riverside cottage near Shepperton-on-Thames, though she still kept open her pretty flat in Stamfordham Mansions, her faithful French maid, Mariette, being in charge.