He followed the game south that fall, taking with him Bob Craig and young Anders. Hundreds of miles south of the caves they came to the lowlands; a land of much water and vegetation and vast herds of unicorns and woods goats. It was an exceedingly dangerous country, due to the concentration of unicorns and prowlers, and only the automatic crossbows combined with never ceasing vigilance enabled them to survive. There they saw the crawlers; hideous things that crawled on multiple legs like three-ton centipedes, their mouths set with six mandibles and dripping a stinking saliva. The bite of a crawler was poisonous, instantly paralyzing even to a unicorn, though not instantly killing them. The crawlers ate their victims at once, however, ripping the helpless and still living flesh from its bones. Although the unicorns feared the crawlers, the prowlers hated them with a fanatical intensity and made use of their superior quickness to kill every crawler they found; ripping at the crawler until the crawler, in an insanity of rage, bit itself and died of its own poison. They had taken one of the powerful longbows with them, in addition to their crossbows, and they killed a crawler with it one day. As they did so a band of twenty prowlers came suddenly upon them. Twenty prowlers, with the advantage of surprise at short range, could have slaughtered them. Instead, the prowlers continued on their way without as much as a challenging snarl. "Now why," Bob Craig wondered, "did they do that?" "They saw we had just killed a crawler," Humbolt said. "The crawlers are their enemies and I guess letting us live was their way of showing appreciation." Their further explorations of the lowlands revealed no minerals--nothing but alluvial material of unknown depth--and there was no reason to stay longer except that return to the caves was impossible until spring came. They built attack-proof shelters in the trees and settled down to wait out the winter. They started north with the first wave of woods goats, nothing but lack of success to show for their months of time and effort. When they were almost to the caves they came to the barren valley where the Gerns had herded the Rejects out of the cruisers and to the place where the stockade had been. It was a lonely place, the stockade walls fallen and scattered and the graves of Humbolt's mother and all the others long since obliterated by the hooves of the unicorn legions. Bitter memories were reawakened, tinged by the years with nostalgia, and the stockade was far behind them before the dark mood left him. The orange corn was planted that spring and the number of prospecting parties was doubled. The corn sprouted, grew feebly, and died before maturity. The prospecting parties returned one by one, each to report no success. He decided, that fall, that time was too precious to waste--they would have to use the alternate plan he had spoken of.