Greatly annoyed and humiliated, he regained his feet and spoke with a laugh to reassure Nan. Just as she answered not to worry, a little singing scream struck their ears; something splashed suddenly close at hand against the rock wall; chips scattered between them. From below, the sound of a rifle report cracked against the face of the cliff. They were so startled, so completely amazed that they stood motionless. De Spain looked down and over the uneven floor of the Gap. The ranch-houses, spread like toys in the long perspective, lay peacefully revealed in the gray of the morning. Among the dark pine-trees he could discern Nan's own home. Striving with the utmost keenness of vision to detect where the shot had come from, de Spain could discover no sign of life around any of the houses. But in another moment the little singing scream came again, the blow of the heavy slug against the splintering rock was repeated, the distant report of the rifle followed. "Under fire," muttered de Spain. He looked questioningly at Nan. She herself, gazing across the dizzy depths, was searching for the danger-point. A third shot followed at a seemingly regular interval--the deliberate interval needed by a painstaking marksman working out his range and taking his time to find it. De Spain watched Nan's search anxiously. "We'd better keep moving," he said. "Come! whoever is shooting can follow us a hundred yards either way." In front of de Spain a fourth bullet struck the rock. "Nan," he muttered, "I've got you into a fix. If we can't stop that fellow he is liable to stop us. Can you see anything?" he asked, waiting for her to come up. "Henry!" She was looking straight down into the valley, and laid her hand on de Spain's shoulder. "Is there anything moving on the ridge--over there--see--just east of Sassoon's ranch-house?"