“Whoosh! They’ll get us, of course, no matter what we do,” said Mac dourly.
The Scot was the gloomiest soul alive — till things got really desperate. Then, when there didn’t seem a chance of escaping death, for some cockeyed reason he got as sure of success as an optimist drunk on champagne.
“They’ll likely do for us if we stick around,” said Smitty. “My vote is, slip out of camp and make ourselves scarce till the chief shows up.”
“Aye,” said Mac.
Josh nodded, too.
The three were not afraid; it took more than a pack of gunmen to affect them that way. It was simply bad sense to wait around till some rat shot you in the back; good sense to stay alive so you could work some more.
So they slipped out of camp, one at a time, and met again near the Donald Duck outcropping. Here Mac balked at going farther.
“I’m stayin’ here,” he said, “till I see what ails this big dead trrree. ’Tis too much it has moved with us not knowin’ why.”
They examined the “walking” tree.
Others had examined it and found it like any other tree. The three aides of The Avenger didn’t find anything out of the way, either, at first, so cleverly was it done.
Then Josh, who had been scraping away at the shale and earth, exclaimed aloud. He had come to the end of one of the roots. There should have been no end. The root should have kept on extending for yards under the surface.
They found more root ends. Then Smitty, with a grunt, tipped the big thing over. Four average men couldn’t have done it, for the extending roots, short as they had been cut, made a wide base. But the giant, with a heave and a snort, tipped it in a hurry. Then there were more exclamations.
The thing was hollow all the way down. At the base, in the hollow, was a clever arrangement of wheels and levers. By lifting the levers you lowered the wheels, jacklike, till the stump was raised on them a few inches. Then you rolled the great dead thing wherever you wanted it, barring too-great irregularities in the ground.
“But why?” gasped Josh.
“Easy,” said Smitty. “This tree was used as a surveyors’ mark in laying out the new roadbed. Somebody knew that. So they moved the mark, which set the tunnel site deliberately at the wrong place. For some reason, the tree-mover didn’t want drilling to start at the correct spot.”
Mac was standing on the big dead stump. He could see farther than the rest from his four-foot elevation.
“Oh-oh!” he said. “A bunch is coming from camp. They’ve found out we left, and they want to locate us.”
“How many?” said Smitty, swelling his giant muscles. “We can take care of any number up to eight.”
“There are a lot more than — Smitty! Look behind you! At the cliff!”
Smitty whirled. And then his bellow of alarm roared out.
Nellie Gray was at the foot of the cliff, at the mouth of an irregular opening that seemed to stop at a great boulder a few feet in. The three were yards from her, but there was no mistaking the diminutive, fragile, feminine figure and the tawny-gold hair, even though Nellie’s back was to them.
Her back was to them because something within the rift had hold of her. They could see a hand, not large, but purposeful, on her throat. They could see her fight wildly, silently.
Then they saw her hauled into the recess out of sight.
Led by Smitty in a mad bull-elephant rush, the three raced toward the fissure. Forgotten were the men coming from the camp. In Smitty’s mind everything else was forgotten, too.
Nellie Gray fighting for her life! That was the payoff for the giant. When he saw a thing like that, there was violent action due.
They got to the recess, and found it wasn’t a recess at all. It was one of the fissures, beginning now to look uncountable in number, leading into the heart of the glass mountain.
They squeezed in. There was no sound from Nellie, and that was bad. That hand at her throat—
They had gone twenty yards over a rough floor when they saw a feminine form again, flitting ahead of them, hanging back as if being dragged.
They rushed to it!
There was a sound behind them like the thudding into place of a bank vault door, magnified many times. Even with Nellie on their minds, the three turned automatically.
They saw that the action which had produced the sound was much as if a vault door had thudded into place behind them.
A slab of solid basalt, many feet through, had been dropped from somewhere in the roof of the tunnel, and had smashed ponderously on the rock of the floor. Now it barred the way they had come, rising sheer from floor to roof, and extending from wall to wall of the rift.
They had been sealed in with tons of stuff as hard and obdurate as smooth, black glass.
Smitty swept his flashlight from the newly-fallen mass.
“No freak of nature ever did that,” he said somberly. “That’s a man-made trap.”
The light stabbed along the passage, and lit on the feminine figure whose distress had drawn them in here.
The girl was laughing, if you’d want to call it that. Her face was twisted with laughter, but it was a kind of sobbing sound that came out, bordering on hysteria.
And the girl was not Nellie Gray.
With her hair lightened, and wearing Nellie Gray’s clothes, she looked like Nellie. But at close range the shape of her face and color of her eyes gave her away. It was Ethel Masterson.
“You’ll die!” she screamed. “You’ll all die! I didn’t get your leader with my trick, but at least I got you, his friends. And your deaths will be a part-payment for my father’s murder.”
Smith glared at the girl.
“I tricked you nicely,” she shrilled. “I grasped my own throat, with my own hand, with my back turned to you, and pretended to be dragged forward by someone. I did it all alone, for vengeance.”
“Very clever,” grated the giant.
There was a second ponderous thud, and suddenly a thick wall of black basalt appeared behind the girl, shutting them all into a thirty-foot stretch of the tunnel.
The girl laughed crazily.
“You’ll die! You’re all trapped!”
Smitty’s look and tone softened. The giant knew distress when he saw it. He knew that this girl wasn’t acting in character; she had been driven half-mad by the conviction that The Avenger had killed her father. She was no murderess. She wasn’t responsible for the things she was doing.
Also, it seemed to Smitty, she wasn’t very bright.
“Aren’t you overlooking something?” the giant said.
She stared at him with a little more sanity in her eyes.
From some place not far off came the sound they had heard before, and had learned to dread. The sound of underground water.
“We’re trapped, yes,” said Smitty, “but you seem to be overlooking the fact that you’re trapped, too. Whatever happens to us, will also happen to you!”
Ethel stared back at the second great slab that had dropped from the tunnel roof to block them off. And sudden bewilderment and terror showed in her eyes.
“Why,” she stammered, “why… that slab… I was to have been on the other side when that dropped, shutting you all in—”
From around the bottom and lower sides of the first slab gushed water. In a torrent it began to fill the cave, rushing in freely but with too much pressure behind it to allow it to run out again.
The level rose several inches a minute. In a good deal less than half an hour it would hit the roof. And there was no way out save the two blocked by the basalt slabs.