Shane by Jack Schaefer

From chapters.ca:
He rode into our valley in the summer of '89, a slim man, dresses in black. "Call me Shane," he said. He never told us more. There was a deadly calm in the valley that summer, a slow, climbing tension that seemed to focus on Shane. "There's something about him," Mother said. "Something...dangerous..." "He's dangerous all right," Father said, ..."but not to us..." "He's like one of these here slow burning fuses," the mule skinner said. Quiet...so quiet you forget it's burning till it sets off a hell of a blow of trouble. And there's trouble brewing."