They came to a part of the border far from the spot which they had disturbed only three evenings before; and Orion was guided by the chattering trolls, for well they knew the haunts of the lonely unicorns. And Earth's evening came huge and hushed, till all was dim as the twilight; and never a footfall did they hear of the unicorns, never a glimpse of their whiteness. And yet the trolls had guided Orion well, for just as he would have despaired of a hunt that night, just when the evening seemed wholly and utterly empty, a unicorn stood on the earthward edge of the twilight where nothing had stood only a moment before: soon he moved slowly across the terrestrial grasses a few yards forward into the fields of men. Another followed, moving a few yards also; and then they stood for fifteen of our earthly minutes moving nothing at all except their ears. And all that while the trolls hushed every hound, motionless under a hedge of the fields we know. Darkness had all but hidden them when at last the unicorns moved. And, as soon as the largest was far enough from the frontier, the trolls let loose every hound, and ran with them after the unicorn with shrill yells of derision, all sure of his haughty head. But the quick small minds of the trolls, though they had learned much of Earth, had not yet understood the irregularity of the moon. Darkness was new to them, and they soon lost hounds. Orion in his eagerness to hunt had made no choice of a suitable night: there was no moon at all, and would be none till near morning. Soon he also fell behind. Orion easily collected the trolls, the night was full of their frivolous noises, and the trolls came to his horn, but not a hound would leave that pungent magical scent for any horn of man. They straggled back next day, tired, having lost their unicorn. And while each troll cleaned and fed his hound on the evening after the hunt, and laid a little bunch of straw for it on which to lie down, and smoothed its hair and looked for thorns in its feet, and unravelled burrs from its ears, Lurulu sat alone fastening his small sharp intelligence, like the little white light of a burning glass, for hours upon one question. The question that Lurulu pondered far into the night was how to hunt unicorns with dogs in the darkness. And by midnight a plan was clear in his elvish mind. CHAPTER XXIX _The Luring of the People of the Marshes_ As the evening that followed was beginning to fade a traveller might have been seen approaching the marshes, which some way south-eastwards of Erl lay along the edge of the farmsteads and stretched their terrible waste as far as the sky-line, and even over the border and into the region of Elfland. They glimmered now as the light was leaving the land.