Knowledge is power. Hence England is compelled to hold her place in the diplomatic intrigues of the world by the employment of secret agents. There are many doors to be unlocked, and to men like Cator, England does not grudge golden keys. Riggs had brought the whiskey and soda, and the man whose career would have perhaps made the finest romance ever written, had drained a tumblerful thirstily, with a laugh and a word of excuse that "the way had been long, and the wind cold." When they were alone again, he twisted the rather stubby ends of his grey moustache, and with his eyes fixed upon the Under-Secretary said: "I should not have disturbed you at this hour, Mr. Chisholm, were not the matter one of extreme urgency." Dudley sat eager and anxious, wondering what could have brought this man to England. A grave and horrible suspicion had seized him that the truth he dreaded was actually out--that the blow had fallen. No secret was safe from Cator. As he had obtained knowledge of the profoundest secrets of the various European Powers in a manner absolutely incredible, what chance was there to hide from him any information which he had set his mind to obtain. "Is the matter serious?" he asked vaguely. "For the present I cannot tell whether it is actually as serious as it appears to be," the other answered with a grave look. "As you are well aware, the outlook abroad at this moment is far from promising. There is more than one deep and dastardly intrigue against us. The diplomatic air on the Continent is full of rumours of antagonistic alliances against England, and even Mercier, in Paris, has actually gone the length of planning an invasion. But a fig for all the bumptious chatter of French invasions!" he said, snapping his finger and thumb. "What we have to regard at this moment is not menaces abroad, but perils at home." "I hardly follow you," observed the Under-secretary.