The Lone Star Ranger by Zane Grey

After nearly six months in the Nueces gorge the loneliness and inaction of his life drove Duane out upon the trails seeking anything rather than to hide longer alone, a prey to the scourge of his thoughts. The moment he rode into sight of men a remarkable transformation occurred in him. A strange warmth stirred in him -- a longing to see the faces of people, to hear their voices -- a pleasurable emotion sad and strange. But it was only a precursor of his old bitter, sleepless, and eternal vigilance. When he hid alone in the brakes he was safe from all except his deeper, better self; when he escaped from this into the haunts of men his force and will went to the preservation of his life.

Mercer was the first village he rode into. He had many friends there. Mercer claimed to owe Duane a debt. On the outskirts of the village there was a grave overgrown by brush so that the rude-lettered post which marked it was scarcely visible to Duane as he rode by. He had never read the inscription. But he thought now of Hardin, no other than the erstwhile ally of Bland. For many years Hardin had harassed the stockmen and ranchers in and around Mercer. On an evil day for him he or his outlaws had beaten and robbed a man who once succored Duane when sore in need. Duane met Hardin in the little plaza of the village, called him every name known to border men, taunted him to draw, and killed him in the act.