The knife trembled as it began its downward swing.
Then, with startling suddenness, an arm shot through the grating behind the Mexican. A black-gloved hand caught Pedro's descending wrist. The huge man's powerful swing was plucked in mid-air. Harry saw a look of distorted amazement come over Pedro. The man released him suddenly. Harry fell to the floor, and his head thumped against the stone.
Though slightly dazed, he could still see what was happening. That single hand which gripped Pedro's wrist possessed superhuman power, for it was twisting the huge Mexican back and forth as though he had been made of straw.
Another thin-gloved hand came through the hers. There was a quick movement, and Pedro was hurled headlong. The machete shot from his hand and clanged on the cellar floor. The big Mexican lay still.
A click and the grating opened. Those hands had pried open the fastening in a twinkling. The bars swung inward. A black figure slipped into the cellar and stood over Harry Vincent, looming like a mammoth bat-winged creature.
It bent forward, and Harry believed that he saw two bright eyes in the depths of the black shape. An exclamation came to his parched lips.
"The Shadow!"
A strange, almost mystic whisper came from the figure that hovered above him.
"Where is Duncan?"
"At the other end of the cellar. Behind a steel barrier."
"In danger?"
"Yes."
"Rest yourself for a minute. Wait until I have gone. Then go there to help him."
The Shadow moved away. Harry could see the back of the strange figure in the cloak as it seemed to blot out the motionless form of Pedro. A flashlight was turned on; it was set on the floor. As Harry leaned against the wall, he could see the face of the unconscious Mexican, in the center of the ring of light.
The Shadow was bending over Pedro. Some quick action was indicated by the trembling of the long black cloak. Harry could not see The Shadow's face, but it appeared as though the man was studying the features of the brute on the floor.
Pedro's body moved as The Shadow seemed to tug at it. Something was happening — rapidly. A full minute elapsed, then came a surprising result that made Harry rub his eyes and gasp with astonishment.
The light was lifted from the floor. It shone on a mirror that was held by a hand. With a single motion, the black cloak and hat were lifted upward, then they fell to the floor. A face was revealed in the circle of light. It was the face of Pedro the Mexican!
As the standing figure turned, Vincent could see the features plainly. They were the perfect replica of Pedro's countenance. Even the scar on the cheek appeared in livid vividness.
The lips moved. They showed a sneer. It was an exact representation of the triumphant expression which the Mexican had revealed when he had poised the machete above Vincent's breast.
The real Pedro lay on the floor, but above him stood his exact duplicate! It seemed incredible — impossible — yet it was actuality!
For one brief instant the face of the false Pedro changed its expression. Then the sneer reappeared. The light was out; the standing figure was gone.
As Harry Vincent rose to his feet and steadied himself against the wall, a weird, unforgettable sound echoed through the vaulted basement.
It was the sound of a laugh — a whispered laugh a mocking laugh that brought a sudden throbbing to Harry Vincent's temples.
It was the laugh of The Shadow!
CHAPTER XVI. THE OLD MAN'S STRATEGY
Isaac Coffran was standing in the center of the front room on the second story. He was facing the curtained doorway, but his eyes were on the floor. A cunning smile was on his lips. He was gloating and triumphant. His hands were behind his back; his pose was one of enjoyable anticipation.
A shadow moved across the floor and extended toward the old man. Isaac Coffran raised his head quickly. He grinned as he saw the leering face of Pedro. The Mexican had parted the curtains and was standing in the doorway. His left hand held the machete; his right arm supported a black bundle.
"Well?" questioned Isaac Coffran.
Pedro's lips parted in an ugly snarl of mirth. The big man tossed the machete on a chair and placed the bundle on top of it.
"Did you find the man in the cellar?" asked Isaac Coffran.
"Si, senor," replied Pedro. "Yes."
"Ah!" exclaimed the old man. "I am glad I sent you down. I thought perhaps the rescuer had slipped out before the curtain closed. Where was Duncan — the young man? In the closing room?"
"I think so."
"He couldn't have escaped. He was too exhausted by the gas. Well, he has five minutes more to wait. What did you do to the other man?"
Pedro pointed to the chair.
"There is his hat, senor," he said. "There is his coat. Pedro can use the machete well. Very well."
The old man chuckled.
"You are useful, Pedro," he said. "But these are useful, too. He pointed to a row of buttons and lights above a table by the door. One by one he indicated them.
"Here," he chortled, "is the gas button. That was first. The second was this light — when Duncan rang from the study. Then this light showed that some one within the cellar had brought down the elevator. How did the man get in? Through a loosely fastened window?"
"Yes."
"Careless of you, Pedro. We must attend to that. But look. I pressed this button. Up came the elevator. This button — down came the steel curtain. Here I released the trap — perhaps the young man has fallen in it. We shall see later. Then" — the old man's face gleamed with fiendish malice — "the last button. The wall is closing. Slowly closing. Soon it will be ended. Listen!"
A faint, distant thumping could be heard from the depths of the house.
"The machete is useful, Pedro," observed the old man. "Quick work — no noise. We will drop that body through the trap, too."
He looked at the Mexican quizzically.
Pedro grinned.
"You look different than usual," said Isaac Coffran. "You must have had some trouble, Pedro. Your scar is a trifle redder than I have ever seen it before. You must have given way to excitement! I never knew you to do that before."
The old man wheeled and faced a clock that hung on the wall opposite the door. Staring toward the dial, he became oblivious to Pedro's presence. Venomously, Isaac Coffran announced the moments that remained.
"Three minutes more," he sneered. "No! Two minutes. The crushing is about to commence. This period is always enjoyable to me. That last minute, when the wall closes over the few remaining feet. The victim is at his last moment of helplessness. This is a rare pleasure, Pedro. I hope you enjoy it as much as I."
He paused, listening, while he stared at the clock.
"Can I be wrong?" he asked. "Impossible! Yet the mechanism has stopped! I can't hear its thumping beats. Can you, Pedro? No. I can't be wrong. There is more than a minute to go! I test it every week, Pedro. It is timed exactly!"
There was no response from the door. Isaac Coffran did not turn. He still watched the clock.
"I wonder if it stopped," he muttered. "I must investigate. Perhaps the body was stretched toward the wall. That must be it. Young Duncan was half unconscious. He may have lain where the other dragged him. A lengthwise body would crush slowly. It might stop the wall — yet the mechanism should still go on, at that!"
The old man swung toward the table. He saw the buttons above it and a startled cry came from him.
There had been little yellow lights over the two buttons which he had last indicated — the button that released the steel curtain and the button that operated the moving wall. Both of these lights were out.
Some one had pressed the buttons!
"Pedro!" exclaimed the old man.
He looked up at the curtained doorway. The Mexican was gone. In his place stood a strange, silent figure — a man wearing a black cloak and hat, the same garments that Pedro had brought upstairs. The cloak seemed to envelop a shapeless form; the hat had a broad brim that obscured the face of the bent head. Isaac Coffran thought that he could glimpse two eyes between the hat and cloak.