He urged the sphere to swifter flight along the range. Miles from the Caves, he swept up over the peaks, and dropped down on the lowlands side. Dusk was deepening rapidly as he raced back toward the White River cataract under the pall of the gathering storm.
Among the boulders on the rough mountainside near the mouth of the Caves he eased the craft down to a gentle landing.
"Wait here," he told Irma. "I'll investigate and see if it is safe to enter the Caves."
They had seen the three men return to the ship, but others might have gone to the Caves after that. Penrun made his way down the slope to the lip of the cataract and the yawning blackness of the abysmal gorge below it.
Overhead the storm was gathering swiftly, and the saffron light of the dying day illuminated the plateau eerily. Half a mile away the Trap-Door City shimmered fantastically in the uncertain light. Penrun repressed a shudder. The Devil's own playground! Thank God, he and Irma would be out of it soon!
He crept down the narrow path that led under the ledge of the trickling cataract. Outside, a bolt of lightning stabbed down from the darkened heavens. Its lurid flash revealed the huge figure of a man, pistol in hand, beside the entrance to the Caves.
Too late to retreat now, even had he wished to. Penrun's weapon flashed first. A scream of pain and fury answered the flash, and the man's pistol clattered down on the rock. The next instant Penrun was helpless in the clutch of a mighty pair of arms that tried to squeeze the life out of him.
"Burn, me, will ye, ye dirty scum!" roared the giant of a man tightening his grip. "I'll break your damned back for ye and heave ye into the gorge!"
Penrun writhed frenziedly, trying to twist his pistol around against his enemy's back, while they struggled desperately about the ledge above the dizzy blackness of the gorge. But the pistol struck the wall beside the entrance and fell under their trampling feet.