"Radioactive!" Nelson muttered incredulously. "A radioactive chemical mass of some sort that's eaten its way into the floor."
Very effectively, that moat of death had barred all entrance into the unguessable farther depths of the Cavern.
He looked up along the wall above the cleft and made out vast twisted cylinders, their metal sides burst and gaping. There was no mistaking what those cylinders were. They were huge tanks.
Had the radioactive mass spilled from those shattered tanks? It seemed obvious and yet—
Nsharra led him to the end of the mass of giant tubes that ran along the walls back to the farther depths of the Cavern. The tubes were all of six feet in diameter, made of unfamiliar metal, massive and thick. He tried to picture them as they must have been once and the picture staggered his mind with suggestions that were pure madness.
Nsharra said, "Most of these strange tunnels are broken. But one of them leads safely over the cleft of cold fire. It is the secret way, found long ago by a Guardian and told only to his successors."
She climbed into the flared ripped end of one of the giant tubes, motioning him to follow. He did so, using his pocket light. The inner wall of the tube was pitted and scored, the metal burned. Yes, burned, like a charred log. And yet it seemed amazingly tough metal. It acted as a shield against the deadly radiation they were crossing.
Numbly Nelson wondered what terrible force had ripped through these giant tubes to scar them so.
Ahead of him, Nsharra came to a place where the tube twisted upon itself. He scrambled with her around the turn. Then, suddenly, he snapped off his light and whispered quickly to her.
"Silence!"