Harry tried to ask further questions, but not a word would Frank reply. He pulled Rattleton from the saddle, and sprang up himself. Then he gave the animal the spur and was away. Frank did not glance over his shoulder to see if the others were following. He thought of nothing but the human game he was after. Would the wretch secure such a start that it would not be possible to overtake him? “No!” came through Frank’s set teeth. “I will run him down!” Round the clump of bushes he guided the horse, and then cut down through the valley toward the spot where he had seen the unknown horseman riding into the timber. Over the stream leaped the horse, up the slope he galloped, and the timber was reached. Then Frank found the very spot where the man’s horse had been hidden, and he struck the trail of the murderous-minded rascal. Now, Eastern boy and Yale student though he was, Frank Merriwell had followed at the heels of the best trailers in this country. He had seen them work, and he had studied their methods, becoming a fairly expert trailer himself. At first what he discovered puzzled him. The tracks of the horse showed quite plainly on the soft ground, but the marks of the shoes did not seem to indicate that the animal had gone toward the timber. “I saw him!” muttered Frank. “It was no optical delusion.” Then he got down on his knees, holding on to the bridle of his horse, and examined the tracks still more closely. An exclamation broke from his lips. “Queer horse that! Never heard of a horse walking on his heels before!” A moment later he sprang into the saddle and was away, but he was riding in a direction precisely opposite that which it seemed the horse had gone! Into the timber Frank plunged. It was not a very wide strip, and he soon passed through it. On the farther side he found the tracks again. The shoes of the horse pointed to the north, but Frank Merriwell rode to the south. The other boys had paused to help Rattleton catch the horse in the pasture, so they were unable to follow Frank closely. Ahead of Merriwell, beyond a field, lay a road. He made straight for a gap in the fence, and there he found the horse had passed through, apparently having turned from the road and taken to the field at that point, judging by the direction in which the shoes pointed. Frank took to the road, gave his horse the spur, and tore along till he came around a bend. Nearly a mile away a horseman was just leaving the road and taking to the fields. He carried a rifle in his hands. “You’re my game for a cool thousand!” thought the boy, triumphantly; “and I believe you have handicapped yourself by the trick you have tried to play.” He rode in hot pursuit, and it was not long before the man discovered he was followed. Then the unknown showed guilt, for he whipped up his horse and tried to run away. “I’ll kill this horse before you shall do it!” grated Merriwell.