"These fellows, my dear Okewood, move in darkness. Very often we have to grope after 'em in darkness, too. They don't get shot, or hardly ever; they are far too clever for that. Between us and them it is a never-ending series of move and countermove, check and counter-check. Very often we only know of their activities by enemy action based on their reports. Then there is another leak to be caulked, another rat-hole to be nailed up, and so the game goes on. Hitherto I think I may say we have managed to hold our own!"

The Chief stopped to light another cigarette. Then he resumed but in a lower voice.

"During the past month, Okewood," he said, "a new organization has cropped up. The objective of every spy operating in this country is, as you may have surmised, naval matters, the movements of the Fleet, the military transports, and the food convoys. This new organization has proved itself more efficient than any of its predecessors. It specializes in the movement of troops to France, and in the journeys of the hospital ships across the Channel. Its information is very prompt and extremely accurate, as we know too well. There have been some very disquieting incidents in which, for once in a way, luck has been on our side, but as long as this gang can work in the dark there is the danger of a grave catastrophe. With its thousands of miles of sea to patrol, the Navy has to take a chance sometimes, you know! Well, on two occasions lately, when chances were taken, the Hun knew we were taking a chance, and what is more, when and where we were taking it!"

The Chief broke off, then looking Desmond squarely in the eyes, said:

"This is the organization that you're going to beak up!"

"Who is at the head of it?" he asked quietly.

The Chief, smiled a little bitterly.

"By George!" he cried, slapping his thigh, "you've rung the bell in one. Okewood, I'm not a rich man, but I would gladly give a year's pay to be able to answer that question. To be perfectly frank with you, I don't know who is at the back of this crowd, but..." his mouth set in a grim line, "I'm going to know!"