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