They crouched and listened, and Nelson heard plainly this time the sound that had warned him-a sound of something slipping and scrambling behind them in the tube, something straining to overtake them.
He had his gun out and ready when Tark's thought came to them. "Where man can go wolf can go! And where Nsharra goes this wolf goes also!"
Nelson relaxed and swore. Tark scrambled toward them, digging his claws into the pitted metal.
"Too late for anger now," he thought to Nsharra. "The outlanders and Shan Kar's men have already landed." He added with a wolfish shrug, "And anyway my Clan is safe now."
Nsharra's hand briefly touched the massive hairy head, but she did not speak. They went on for what seemed a long time in the tube. Then it debouched into a round gigantic metal chamber that looked to Nelson very like part of a turbine — a turbine built by giants for some unguessable purpose.
"Giant tubes that could be jet-tubes!" he said half aloud in a stunned voice. "This colossal turbine — and the radioactive chemical from the tanks, that could be fuel—"
"Come," said Nsharra and he followed her, the wolf keeping close to them as though awed by this forbidden place.
As they stepped out of the shattered turbine, well beyond the deadly cleft, Nelson could look into the shadowy farther spaces of the Cavern that previously the cold radiance had hidden from him.
He was not really surprised at what he saw. Shocked, stunned, awed, but not really surprised. Before him stretched the Cavern, vast, incredible, shadows glooming thicker as the eye went back into it.
And its half-seen, half-guessed shape was the shape of a torpedo, tapering from blunt stern to slender point. A sharp, clean point to cleave the air, to cleave, perhaps, the vast gulfs where there was no air, where only the stars rubbed shoulders with eternity!