Behind Alystra, struggling with the weight of their projectors, came Narrillian and Floranus. Alvin wondered briefly why tose projectors were so heavy, since it would have been such a simple matter to provide them with gravity neutralizers. He was always thinking of points like this, even in the midst of the most desperate adventures. When such thoughts crossed his mind, it seemed as if the structure of reality trembled for an instant, and that behind the world of the senses he caught a glimpse of another and totally different universe…

The corridor ended in a blank wall. Had the arrow betrayed them again? No-even as they approached, the rock began to crumble into dust. Through the wall pierced a spinning metal spear, which broadened rapidly into a giant screw. Alvin and his friends moved back, waiting for the machine to force its way into the cave. With a deafening screech of metal upon rock-which surely must echo through all the recesses of the Mountain, and waken all its nightmare brood!-the subterrene smashed through the wall and came to rest beside them. A massive door opened, and Callistron appeared, shouting to them to hurry. («Why Callistron?» wondered Alvin. «Whats he doing here?») A moment later they were in safety, and the machine lurched forward as it began its journey through the depths of the earth.

The adventure was over. Soon, as always happened, they would be home, and all the wonder, the terror, and the excitement would be behind them. They were tired and content.

Alvin could tell from the tilt of the floor that the subterrene was heading down into the earth. Presumably Callistron knew what he was doing, and this was the way that led to home. Yet it seemed a pity…

«Callistron,» he said suddenly, «why don’t we go upward? No one knows what the Crystal Mountain really looks like. How wonderful it would be to come out somewhere on its slopes, to see the sky and all the land around it. We’ve been underground long enough.»