Free Hell's Gate by Dean Koontz

no matter how hard he tried, he could not draw breath quietly.
        In desperation, he came up with a plan of sorts, the only thing that might work. He scrambled down the embankment and worked his way out on the ledge that led to the cave where he had found the three trunks and where he had slept for two weeks. Halfway along it, he stopped and looked overhead. There were rocks, roots, and branches of scrub brush to cling to. It didn't look like the easiest of plans, but it was all he had. He grabbed some protruding rocks and started climbing up.
        Three minutes later, gasping, his hands raw from the climb, from skinning them on rocks, burning them on branches, he was perched eight feet above the ledge, only a foot from his head to the top of the embankment. If the killer did either of two things, Salsbury's plan might work. If he did neither, Victor knew his worries would be finished anyway, finished by a sharp, sparkling blade of yellow light
        If the killer followed Salsbury's trail perfectly in some mysterious fashion, he would go down the rain cut and onto the ledge. In that case, Victor would drop on him from his higher perch, feet first. Hopefully, both feet ploughing into the stranger's head would weigh any subsequent fight in Victor's favor-and just might crush the man's skull straight away. If, instead, the killer came to the embankment and searched along it, standing near the edge, Victor could reach up with one hand, holding to the rocks with the other, grab an ankle, and attempt to topple his adversary into the creek thirty feet below. There were a lot of sharp, lovely rocks in that creek. And even if the fall did not kill him, it should sure as hell slow him down some.
        Victor waited.
        In a few moments, he heard the stranger coming out of the trees onto the smoother surface near the bank. He walked to the edge some ten feet to Victor's left and stood looking across the creek to the black wood beyond. Even in the darkness, here away from any light source but the thin moon, his eyes glowed dully.
        Salsbury pressed himself flat against the cliff, hoped he looked like a rock. The killer began walking along the embankment, examining the far shore of the creek where several feet of mud would have left a trail of his escaping prey. He stopped a foot to the right of Salsbury's position, making it awkward for the man to reach up and grab his ankles. But he would move away, Salsbury realized, making contact even more difficult. Tensing, holding tightly to a branch with his left hand, Victor reached up quickly to grasp the killer's ankle.
        For a moment, all seemed lost. His hand brushed the stranger's leg too lightly to gain a grip. The man jerked in reflex but moved closer instead of farther away. Salsbury grabbed again, yanked, felt the man's foot going out from under him. He risked a glance up, saw the killer flailing for balance. He pulled harder, almost lost his own hold, and sent the man crashing over the side into the water and rocks below.
        Salsbury wasted no time in launching himself up, pulling over the cliff edge and kicking onto level land. He crawled back and looked into the creek. The killer was lying face down in the water, very still. Salsbury laughed; his throat was so dry that the laugh hurt, made] him cough. He sat up, watched the stranger for a few more moments, then started to get up with the idea of going down and examining him to see if he could learn anything. Then he saw the killer was starting to move…
        His face had been under the water long enough to ensure his death, but here he was kicking again. He rolled onto his back, his flat blue eyes staring up at Victor with malevolent intent.
        Salsbury turned and ran back toward the house, his mind swelling like a balloon ready to burst. He wondered how long he could hold onto his sanity in this nightmarish scene where the pursuing monster could not be killed. His only chance now