It ended in a sheer cliff of weathered stone. Vanning reeled toward the barrier. He could not return. The North-Fever drove him on remorselessly. He had to climb that wall of rock, or die. And he could not climb. He fell, rose, and fell again. In the end he crawled. He crawled to the foot of the cliff and dragged himself upright. He fell forward, as though trying to press his body against the towering wall that lifted to the writhing grey clouds-- Fell--through the stone! He toppled through the rock curtain as though it were non-existent! Instantly intense blackness closed around him. Hard stone was under him. His mind was too dulled to wonder. He knew only that the way north was still open. He crept on through darkness, leaving a trail of blood behind him.... The ground dropped from under him. He crashed down on a mound of moulded vegetation. Before the shock had passed, the living dead man was moving again. He crawled forward until his way was blocked by a perpendicular wall. Gasping dry-throated sobs, he clawed at the barrier with broken, bleeding finger-tips. To left and right, an arm's length away, were other walls. He was in a pit. The sane part of his brain thought: "Circle around! There may be some way out!" But Vanning could not circle. He could only move in one direction. That was north. He fumbled blindly at the wall, until unconsciousness came at last.... Twice again he awoke, each time weaker, and twice again he slept. The fever, having passed its peak, dwindled swiftly. At last Vanning awoke, and he was sane. No longer did he feel the relentless urge to turn north. He lay for a little while staring into the blackness, realizing that he was once more in full command of his traitorous body. There was little life left in him. His tongue was blackened and swollen till it filled his mouth. He was a scarecrow, nearly naked, his bones sharply defined through his skin. It was an effort even to breathe. But death would not be long in coming--now.... II Dying is an uncomfortable business, unless a man is drugged or insensible. Vanning found it so. Moreover, he wasn't the sort of man who would give up without good cause. Weak as he was, nevertheless he was still too strong to lie in the dark, waiting. Laboriously, he got to his hands and knees and commenced a circuit of the pit. He expected nothing. But, at the southern end of his prison, he was astounded to find a hole in the wall easily large enough to admit his body. Feeling into the blackness, he discovered the smooth floor of a passage. Good Lord! It had been there all the time, during his tortured imprisonment in the pit. If he had only searched before-- But he could not have done so, of course. Not with the North-Fever flaming in his veins.