They split up. Benson went into the tunnel he had selected and down its smooth floor, with his pale and icy eyes piercing the gloom at the end of his flashlight’s ray, almost like the eyes of a cat.
He felt the coolness and dampness after he’d gone less than a hundred yards, with the light still visible behind him in the central chamber. He went very slowly after that. A subterranean lake or stream was nearby.
He got to it in another thirty yards. He stood on a stone ledge and peered down — straight down.
There was a chasm about thirty feet wide. Filling it from wall to wall was black water that rushed swiftly but soundlessly. It came out of blackness and went into blackness. Across from where Benson stood was blank rock. The tunnel ended in this deadly stream.
Behind him, in the temple chamber, Nellie’s wild scream suddenly rang out. There was a dull, grinding boom!
The solid floor of the tunnel trembled. There was an avalanching roar from the temple chamber. And suddenly Benson was not standing on anything.
He had warned of the deadly Aztec traps, but he had not paid sufficient attention to his own warning. The ledge he’d been standing on was part of such a trap. The explosion in the distance had set off some rock lever, perhaps a dozen feet away, that acted on the ledge.
And the ledge had dropped suddenly from under Benson like a sprung trapdoor.
He plummeted down through darkness, with his flashlight hitting the water and winking out. He heard the stone ledge splash into the ebony stream. Then he hit the rushing depths himself.
As he struck, he was thinking of something. From the plane, there had been no glimpse of the lake or river anywhere near. Wherever this stream came above ground — if it ever did — the intervening distance would drown a man a hundred times over before air and open sky could be reached again.
He went down and down into the icy water which bore him on its smooth and silent rush — toward blackness.
CHAPTER XVI
One Way Out
The entrance to the temple room was blocked so that an army of elephants could not have gotten through to outer air. Several dozen monolithic slabs, each weighing tons, had slid from the ponderous temple roof and shut the temple forever from the outside world.
Smitty got from the depths of his tunnel first. He was running, for all his vast size and weight, like a fleet youngster. He emerged into the rear two-thirds of the room, which was all that was left.
“Miss Gray!” he yelled. “Nellie—”
He stopped. She wasn’t under the rock pile locking them in here forever. She was crouching at the rear wall, with her hands over her face. The slide had missed her by only a few feet.
She looked up at Smitty’s cry, gray eyes wild.
“Borg!” she cried. “It was Borg. I saw him, at the entrance. He set off one of those little bombs and trapped us in here.”
“So — the gang got the jump on us!” said Smitty, hard-eyed. “We weren’t as smart — or as fast — as we thought we were. Chief! Oh, chief!”
MacMurdie stumbled from the tunnel he had been exploring, followed within a few seconds by Chandler. They were white-faced and shaken.
Dick Benson did not come from his tunnel.
“Where’s the chief?” said MacMurdie, anxiety for his boss overshadowing fear for himself. “Why doesn’t he come out of there?”
They watched the tunnel, breathlessly. There was no sound from within, no sight of the white, dead countenance, and the icily flaming pale eyes.
“We’d better go down—”
They hurried down Benson’s tunnel — all of them, with Nellie’s hand clasped in Smitty’s great paw to keep her from tripping. They got to the black death of the river. And there was no sign of Benson.
“He must have… fallen in,” faltered Nellie, swaying.
“The chief?” said Smitty. “Not him! He could walk a tightrope over Vesuvius and not fall.”
“There’s no place else he could be,” said MacMurdie, frosty-blue eyes filled with a dreadful certainty.
Chandler pointed to the brink of the twenty-foot drop down to the water. There, the outline of the place where the overhanging ledge had been could be plainly seen.
“A stone slab collapsed under him,” said Chandler. “A mountain goat would fall, if the ledge he stood on fell under him.”
There was a vast and horrible silence, while the wind fanned up from the narrow chasm, stirred by the noiseless rush of the water.
Smitty, voice strained and hoarse, said:
“Maybe we can get out ourselves. Better to try than just stand here looking into that river.”
“There’s no way out of here,” said Chandler, eyeing the blank wall across the deep crack in the rock. “And my tunnel ended in a little tomb, with solid walls. No way out there.”
“The one I was in just stopped,” said Smitty.
MacMurdie, peering at the river with suffering blue eyes under sandy ropes of eyebrows, shrugged a little.
“I didn’t get to the end of mine. There might be a way out there. I couldn’t tell.”
“Then we’ll go down that one,” Smitty said. “Take it slow, everybody. Keep close together. And hang onto your flashlights!”
They went back to the central chamber, which had become a tomb with the rock seal over its mouth. They went down the tunnel MacMurdie had explored a little way.
Long before that tunnel ended, they would have gone back — if there had been any hope to go back to. The underground tunnel twisted and turned until they were hopelessly lost. Every few yards, some other tunnel laced into it. Methodically they explored each of these, finding an end after a dozen or a hundred steps. Many of them became natural fissures instead of artificial tunnels, after a few feet. The ground here was honeycombed with caves and runways.
“We’ll never get out!” cried Nellie.
“Maybe a little farther on,” said MacMurdie. As usual, when things really looked desperate, the dour Scot was optimistic. When things were normal he gloomily predicted disaster; when they looked impossible, he grew almost cheerful.
“We’ll be comin’ to a way out—” he said. And then he stopped talking. And the rest stopped walking. They were at the end of the parent tunnel — their last hope. And that end was black.
They looked at each other, ghostly in the fading light of the flashlights. Then, as the illumination faded a little more, Chandler cried out.
“At the very end there! Where the tunnel goes to a blunt point! Look!”
They all stared, and Nellie’s gasp was audible.
They could see a tiny scrap of light there; a postage-stamp-sized square of daylight. They scrambled forward.
There had been blank rock wall at the end of this tunnel. The wall of some low cliff. But, ages past, a tree had got its roots in crevices near the tunnel. Roots had swelled through the years, chipping off rock slabs, till now there was an opening.
But the opening was plugged by the tree itself, a hardwood, over a foot in diameter, with a mass of tangled roots filling the end of the tunnel.
Chandler’s shoulders drooped. His voice was quiet but resigned as he said:
“We’re still stuck. We can’t bore up through the heart of that tree with nothing but penknives. And to remove the tree we’d need dynamite.”
Mac turned his frosty-blue eyes on Smitty’s massive bulk.
“We’ve got dynamite,” he assured the engineer. “Only it walks on two legs and calls itself Smitty. Whoosh! Ye can tumble that thing, can’t ye, Smitty? The trunk of it must slant out of balance on the other side, growin’ out of a wall as it does.”
Smitty was looking thoughtfully at the roots.
“Dig under ’em so I can crawl in there, and we’ll see,” he said doubtfully.