Deathwatch by Robb White

"A young college student named Ben is hired to act as a seven-day guide for a “big wig” executive named Madec who is hunting for Bighorn sheep in a remote region of the desert. Ben knows the area well having grown up locally with his uncle learning to hunt and camp in the wilderness. On the third day out, a terrible accident occurs when Madec shoots at what he thinks is a ram but turns out to be an old hermit. Madec wants them both to lie to the authorities and leave the dead man in the desert. Ben insists on taking the body back to civilization, despite offers of hush money to remain silent. The desperate man will do anything to avoid the potential publicity and jail time that may result from the investigation, including forcing Ben to strip and wander in the brutal heat without food, water, or clothing. Ben tries to outwit Madec but the city slicker doesn't leave anything to chance, removing the clothing from the dead man as well as any provisions from his makeshift camp. Ben is lucky to find a slingshot and a dozen or so lead shot hidden in the camp

With his feet badly cut and in dire need of water Ben scales an improbable butte without any climbing gear but is spotted by the hunter. No longer willing to let nature take its course Madec shoots Ben in the arm, intending to kill him. Ben is able to locate a cache of dirty water and shoot birds for food. To his dismay, Madec is now using ropes and pegs to scale the monolith in pursuit of his quarry. Ben must take the fight to Madec or be hunted like an animal in a tree. His plan involves coming down at night and burying himself in the sand near the camp using the tubes of his slingshot to breathe and listen for movement. Once Madec has scaled most of the way up the wall of the rock, Ben attempts to leave in the jeep but the rotor has been removed. He sets fire to the tent to attract attention to the camp but to distract Madec. When the man comes hurrying back to investigate Ben tries to incapacitate him with