The appalling grey barrenness, the height of the frowning ramparts which surrounded him on all sides, except the narrow opening to the sea. The absolute inaccessibility of those frowning walls, and the melancholy scream of the thousands of gulls which haunted the place. It was tremendous. It was terrible. But added to all these things was a discovery which he made almost upon the instant. With the instinct of personal security his eyes sought the high-water mark upon the beach. There was none. It was high up on the cliff sides at no point less that ten feet above the highest point of the beach. Herein lay the terror of the cove which lived in the minds of the dwellers upon the moors. Here was its real terror. A rising tide, and the secret of the smuggler's cavern undiscovered, and--death! He smiled as he thought of the name given to the entrance to the cove. Hell's Gate! It was surely---- "Ahoy!" The cry echoed about the grey walls in haunting fashion. Ruxton was startled out of his reverie. In a moment his repulsion at what he beheld was forgotten. He remembered only his purpose, and his searching eyes gazed out over the water. "Ahoy!" he replied, when the last echo of the summons had died out. He could see no boat. He could discover no human being. And--it was a man's voice that had hailed him. For some moments a profound silence prevailed. Even the gulls ceased their mournful cries at the intrusion of a human voice upon their solitude. Ruxton searched in every direction. Was this another surprise of this extraordinarily mysterious place? Was this----? Quite suddenly his gaze became riveted upon a spit of low, weed-covered rock, stretching out into the calm water like a breakwater. There was a sound of clambering feet, and as his acute hearing caught it, a sort of instinct thrust his hand into his coat pocket where an automatic pistol lay. Then he laughed at himself and withdrew his hand sharply. The figure of a man scrambled up on to the breakwater. They stood eyeing each other for several thoughtful moments. Then without attempting to draw nearer the stranger called to him. "Mr. Farlow, sir. This way, if you please." Without hesitation Ruxton crossed over to him and scrambled on to the rocks. "You are from----?" he demanded. The question was put sharply, but without suspicion. "The lady's waiting for you out there," replied the man simply. "We haven't much time, sir. You can't come in here on a rising tide, and you can't get out of it either. It's hell's own place for small craft, or any craft for that matter on a rising tide." He threw an anxious glance at the water. Ruxton was gazing down at the little boat lying the other side of the natural breakwater. It was a petrol launch of some kind, but small and light as a cockle-shell. There was another man in the stern, and he observed that both he and the man beside him were in some sort of uniform. "I didn't see you come in," he went on curiously.