Rupert was almost the centre of the gang, and he noticed that his own warder, who was just in front, was only just visible in spite of his dark uniform. As he reached the gate 303 gripped him by the arm, dropped on his knees behind the wall and disappeared. At this moment the chief warder gave the order to halt, and his heart flew into his mouth, for he thought 303’s action had been seen. But the sound of some one shouting at the horses, and the chief warder’s voice raised in angry question, reassured him. Without thinking of what he was doing he dropped on his face and crawled rapidly down the side of the wall. At the same moment the order to march was given and the noisy beating of his heart was drowned by the creaking of the waggon as it lumbered past. He lay perfectly still, flattened against the wall. He wondered why he heard no shot or other indication that they had been seen. The rear guards passed within six feet of him, and when their black forms were swallowed up by the white fog, he realised that their absence from the gang would not be discovered until they reached the prison. Leaping to his feet he ran along the wall, and almost immediately fell over 303, who was crouching against it. "Quick, for God’s sake follow me!" he whispered. "We must make for Beardown. This fog may blow away at any moment." They ran like hares; scrambling over the walls, falling into holes, stumbling on rocks, Rupert intent only on reaching Wistman’s wood before the fog lifted. He had nothing to guide him but the knowledge of the direction in which he originally started from the wall and the moorman’s instinct to prevent him from travelling in a circle, which is the inevitable fate of every one lost in a fog. They dropped on to a road, Tavistock Road. "Come on, we are right now!" Rupert cried excitedly. They scrambled over the wall and raced down the steep hillside. Suddenly they saw the gleam of water below them, bushes and stones appeared. They had left the fog behind, the valley was clear. As they plunged across the river and breasted the steep hill they saw the blessed fog shutting out Beardown Farm and all the tors above it. "Quick! we must get up with the fog before we are seen. Thank God, there is no one in sight!" But poor 303 was no moorman, and he was already dropping behind. "I can’t do it, 381; go on without me!" Rupert turned back and, taking him by the arm, pulled him down into a little hollow behind a huge furze-bush and laid him on his back. "You’re only winded; we have run over a mile; you’ll get your second wind in a minute," he whispered. "But we must not wait here a moment longer than absolutely necessary. If the fog should lift now, we are certain to be taken. I am going to make for Hartland Tor, which is close to my father’s house; there is an old, disused mine below the tor in which we can hide for the present." Boom! A dull explosion echoed across the hills. "What’s that?" exclaimed 303.