Partly because they were going the same road--partly because his curiosity was awake--he followed him through the heather, keeping a sharp eye meanwhile, for again and again the man upon the track would swing suddenly about and send his gaze ranging the hill-side for fear of being followed by the people on the shore. But always he did so with the utmost haste, urging the pony onwards after each halt, as though he feared the approach of night, or something that Rob knew nothing about. And so they reached Loch Arkaig, and on the shore of the loch the man seemed to hesitate and take thought, and then hitching the pony to a tree he conveyed the casks to the sand beside the edge of the heather, and flinging off his coat, drew a spade from a hidden place and commenced to dig. Twilight had come, and so shadowy had the shore grown that Rob crept nearer, wriggling through the tufts of heather and rock as noiselessly as an Indian. Suddenly, however, he saw the head and shoulders of some one else silhouetted against the grey surface before him, a man who crouched and ducked his head as the digging ceased or recommenced upon the beach with the same care that he himself was practising. It was evident to Rob that there was more in all of this than he had imagined. At last, apparently satisfied, the watcher began to retreat towards him, running on all fours up the hill-side. So rapidly did he come, indeed, that Rob had no time to roll out of the way, and with a swift bound the newcomer flung his full weight upon him, uttering no sound whatever, and together they rolled over and over in each other's arms. One moment Rob was uppermost, then the other, who seemed all arms and legs and sharp clawing fingers. Twice Rob felt his throat gripped and two thumbs upon his windpipe, and each time he managed to jerk his head away. Then with a swift dive of his right arm he reached the knife in his stocking, and pulling it out he plunged it into his assailant's shoulder. It was a small blade, ill-fitted for dangerous work such as this; but a thin scream told him that he had penetrated the man's thick great-coat. Then perceiving his opponent jerk his head about with the pain, Rob clutched a heavy stone and driving it against his temple sent him senseless upon the ground. It was a narrow escape, but fortune had apparently come to his aid in the nick of time. With a gasp of relief he sprang to his feet, when out of the darkness a voice said: "Stand, or I fire!" and the cold barrel of a pistol was rammed against his cheek. He had forgotten the man upon the shore. "I am unarmed," gasped Rob; "and it is the man upon the ground whom you should guard against, not me."