Shannach—The Last

Even in this grip of alien horror a man could not throw away his lifetime goal ... not stand idly by as endless rows of alabaster shapes, seated in their chairs of stone, thought-ruled this gargoyle planet from the dead blackness of deep Mercurian caverns.
It was dark in the caves under Mercury. It was hot, and there was no sound in them but the slow plodding of Trevor's heavy boots.
Trevor had been wandering for a long time, lost in this labyrinth where no human being had ever gone before. And Trevor was an angry man. Through no fault or will of his own he was about to die, and he was not ready to die. Moreover, it seemed a wicked thing to come to his final moment here in the stifling dark, buried under alien mountains high as Everest.
He wished now that he had stayed in the valley. Hunger and thirst would have done for him just the same, but at least he would have died in the open like a man, and not like a rat trapped in a drain.
Yet there was not really much to choose between them as a decent place to die. A barren little hell-hole the valley had been, even before the quake, with nothing to draw a man there except the hope of finding sun-stones, one or two of which could transform a prospector into a plutocrat.
Trevor had found no sun-stones. The quake had brought down a whole mountain wall on his ship, leaving him with a pocket torch, a handful of food tablets, a canteen of water, and the scant clothing he stood in.
He had looked at the naked rocks, and the little river frothing green with chemical poisons, and he had gone away into the tunnels, the ancient blowholes of a cooling planet, gambling that he might find a way out of the valleys.
Mercury's Twilight Belt is cut into thousands of cliff-locked pockets, as a honeycomb is cut into cells. There is no way over the mountains, for the atmosphere is shallow, and the jagged peaks stand up into airless space. Trevor knew that only one more such pocket lay between him and the open plains. If he could get to and through that last pocket, he had thought....