The wolf circled the wall of stones and also made for the cave. Sundown had arrived a little ahead of him. The top of Sundown's head appeared for an instant; then vanished. The wolf backed snarling against the wall as Chance leaped in. When Sundown's head again appeared, the whirling mass of writhing fur and kicking legs had taken more definite shape. Chance had fastened on the wolf's shoulder. The wolf was slashing effectively at the dog's side. Presently they lay down facing each other. Chance licked a long gash in his foreleg. The wolf snapped as he lay and a red slaver dripped from his fangs. Not twelve feet away, Sundown gazed upon the scene with fear-wide eyes. "Go to it, Chance!" he quavered, and his encouragement was all but the dog's undoing, for he lost the wolf's gaze for an instant, barely turning in time to meet the vicious charge. Sundown groaned as the wolf, with a slashing stroke, ripped the dog's neck from ear to shoulder. The stones in the enclosure were spattered with red as they whirled, each trying to reach the throat of the other. Suddenly Chance leaped up and over the wolf, lunging for his neck as he descended. The wolf rolled from under and backed toward the cave. "Hey!" yelled Sundown. "You can't come in here!" Chance, weakened from loss of blood, lay watching the wolf as it crouched tensely. Again the great gray shadow lunged and a bright streak sprung up on the dog's side. "Gee Gosh!" whined Sundown; "he can't stand much more of that!" Undoubtedly Chance knew it, for he straight-way gathered himself and leaped in, diving low for the wolf's fore leg. As the wolf turned his shoulder, Chance again sprang over him and, descending, caught him just behind the ear, and held. The wolf writhed and snarled. Chance gripped in and in, with each savage shake of his head biting deeper. In a mighty effort to free himself the wolf surged backward, dragging Chance around the enclosure. Sundown, rising from the cave's mouth, crouched before it. "You got him! You got him!" he cried. "Once more, now!" The body of the wolf quivered and sagged, then stiffened as if for a last effort. Chance held. They were both lying on the stones now. Chance with fore feet braced against the wolf's chest. Presently the dog gave a final shake, drew back, and lay panting. From head to flanks he was soaked with blood. The wolf was dead.