C.Q.D.! The signal of "extreme danger." Well, I rather thought it was!

Where I stood I was in deep shadow, and my face could not possibly be seen. I was much the same height and build as the dead man, and Vargus ran down the cave without the least suspicion. He had gone to his left, my right, to where I had already seen a pale light, and I followed him, more slowly, at a distance of some ten yards. It was a natural instinct enough. My only idea was to silence him, find Constance, and fly from the horrible place. I could not know that I was making a fatal mistake.

I was running forward into complete understanding. The great cave turned a little to the right. It opened out every second until at length I saw the mouth, wide as that of the largest-sized hangar on an aerodrome, flooded with moonlight!

Opposite, sixty yards away, was a precipitous wall of black rock; between it and the mouth of the cave a terrible chasm, which fell sheer to the water. It was all clear now. Far above, on the top of the cliffs, was that fenced-in part with the "dangerous" notice boards. You will remember that I had lain down by the side of this fence and peered downwards. I had looked into the same gulf that I was now looking into from a much lower altitude. And the rock there overhung so greatly that there was no possible indication of the cave mouth where I now stood.

Moreover, the cave itself turned inward from the sea, running parallel to the cliff. From the sea, as from the land, the opening of the cave was entirely hidden.

Vargus was fumbling at a switch-board. He pulled down a vulcanite handle; there was a green spark, and lights at the top, bottom and sides of the entrance glowed out brightly.

Imagine an illuminated rabbit-hole in the side of a railway embankment, and you have an exact miniature of what this vast secret cave had now become. Go a little further and think of a bat whose lair was in this hole, and was guided to it by the lights....

Vargus snapped another and smaller switch. I watched him with a sense of complete detachment. I knew, as well as if I had been told, that he was lighting guiding lamps somewhere on the two headlands that guarded the entrance to the cave outside. No thought of danger came to me; I think joy at this complete discovery, and wonder at the stupendous cunning and achievement of it all were my only emotions.

"They may be here at any moment, Feddon. I tell you I don't like it at all. I told the Chief that it was madness not to lie low for a bit. But you know what he is. The Government has got the tip somehow, the Cornish seas are humming with enemies. That fellow, Custance, is smart as they make them...."

He was moving towards me as these words came from him in a nervous, disjointed stream of words. Then he saw me, and stopped bang in the middle of a sentence.