The Rangeland Avenger by Max Brand

Toward the flat-topped mountain, with the feeling of his fate upon him, Bill Sandersen pushed his mustang through the late evening, while the darkness fell. He had long since stopped thinking, reasoning. There was only the strong, blind feeling that he must meet Sinclair face to face and decide his destiny in one brief struggle.

So he kept on until his shadow fell faintly on his path before him, long, shapeless, grotesque. He turned and saw the moon coming up above the eastern mountains, a wan, sickly moon hardly out of her first quarter, and even in the pure mountain air her light was dim.