The Diamond as Big as the Ritz

A prep school student named Percy Washington becomes friends with his schoolmate John Unger. Percy invites John to spend the holidays at his family's isolated Montana mansion. It sits atop a mountain of solid diamond. John begins to worry about his safety when he learns the the father, Mr. Washington, is paranoid about his wealth. He shoots down planes that fly over the house and then kills the pilots. The crazed patriarch does the same with children who drop in.