“I tricked you, Polmore. As soon as I left my watch on the desk, you changed your tune. You were willing then — anxious — to stay here. You are the traitor — you, the man I trusted!”
Polmore quailed beneath the professor’s severe gaze. He tried to talk, but only wordless gasps came from his trembling lips. It was plain that Polmore was an amateur accomplice. The professor took advantage of the fact.
“You have been long in my employ,” he declared. “Therefore, your treachery began at a recent date. Some one bribed you to betray me. Who was the man?”
“He — he called himself Satterly,” stammered Polmore. “Reginald Satterly. But — but I’m not sure that was his name. He was a tall man — tall, with a red mustache — red hair — and he wore a monocle.”
“Did he talk like an Englishman?”
“Yes — but I think he was faking it. He was disguised — I’m sure of it — when I met him in New York. He — well, he offered me a job at first. Then he paid me a thousand dollars. He wanted me to make sure whether or not you had the plans.”
“Have you seen him since?”
“No, sir. Truly, I haven’t. I met a man that works for him. A rough-looking chap named Nuland. In a cottage on the mainland. I—I signaled Nuland to-night.”
“When you pretended to be looking for Bragg?”
“Yes, sir.”
“Where is Bragg?”
“He went to New Haven. He asked me to speak to you this afternoon. I told him later that I had, that you had said he could go. He won’t be back until to-morrow morning.”
“I see. You thought it might be easier with Bragg out of the way.”
“Yes, sir.”
PROFESSOR WHITBURN turned to Stephen. The faithful man was ready. He had listened while the professor had forced the full confession from Polmore’s lips. Stephen advanced and pressed his revolver against Polmore’s ribs. He backed the secretary into a corner.
“Hold him there, Stephen,” ordered Whitburn. He glanced at his watch on the desk. “It is now five minutes past ten. We have not long to wait.”
“For what, sir?”
Stephen put the question without taking his eyes from Polmore.
“For a solution to our problem,” chuckled Professor Whitburn. “We shall turn Polmore over to a person who will question him further. Perhaps we can gain more facts pertaining to the true identity of this briber who called himself Reginald Satterly.
“As for you, Polmore, you can forget all about those plans that I received from Commander Dadren. So can the man who bribed you. The plans were of no use to me. When I suspected that their hiding place was known, I destroyed them.”
As he spoke in a dry tone, the old professor was stroking the cat upon the window sill. As he paused, he felt Quex arch his back.
Alarmed, Whitburn turned toward the door. A sudden gasp came from the old man’s lips. Stephen heard it. He turned; then sullenly dropped his gun.
A man was standing in the doorway. Sallow-faced, with black mustache and hair, he wore an evil leer. He was holding a revolver, covering those within the room. Behind him were three ruffians, also carrying leveled guns.
Eric Hildrow had arrived.
A TROUBLED look came over Professor Whitburn’s thin countenance. Trapped, the old inventor knew that this enemy had heard his final words to Polmore. Moreover, Whitburn recognized that Hildrow — though different from Polmore’s description — must be the master plotter.
Eyeing the professor, Hildrow sneeringly revealed the very fact.
“I am Reginald Satterly,” scoffed the disguised man. “Also Logan Collender, whom you now see. You are right: I am disguised. Disguised when I am Satterly; disguised when I am Collender. Moreover, those identities are but a few of the many that I can assume.
“My real name; my true personality — those would not concern you. I prefer to keep them to myself. As Satterly, I bribed Polmore. As Collender, I command these men who are with me. They have watched this island from the mainland.”
A pause. Twisting, the lips beneath the black mustache formed a sour, cunning smile. Then Hildrow spoke in an insidious tone.
“Fortunately,” he remarked, “Polmore left his key outside the door, with a note beside it. He informed me that he would do so when he flashed his signal to the mainland. We expected to find you alone, Professor Whitburn.
“You are right in assuming that I came to obtain those duplicate plans. But you did not divine the purpose for which I wanted them. I intended to destroy those plans. You have saved me the trouble.
“All that remains is the elimination of yourself. For good measure, I shall dispose of this man Stephen also. You will not live, professor, to tell of this invasion, nor will Stephen be alive to state how you died.”
With this pronouncement, Eric Hildrow turned to growl an order. Nuland advanced, followed by the others of the evil crew. Professor Whitburn and Stephen stood helplessly awaiting the doom that was to be theirs.
Yet the old inventor was unflinching. Despite the closeness of death, he still had hope of rescue. He had sent his message to The Shadow.
CHAPTER V
THE CLOSED TRAP
WHEN Eric Hildrow had led the way into the house on Death Island, he had adopted one precaution. He had left a man on guard in the boat which the raiders had used to reach the isle. This fellow was waiting close beside the little dock that lay on the shore below the house.
The guard did not know what was taking place within. A dozen minutes had passed since Hildrow and the crew had left. At first, the watcher had speculated on how soon the raiders would return. He had been looking into the darkness that shrouded the big house.
Then his eyes had turned. He had heard a distant sound, high above the mainland. It was the rhythmic purr of an airplane motor. Staring at an angle toward the sky, the lone guard tried to make out the night flyer’s lights.
He saw no blinks in the darkness. That surprised him, for he had located the direction from which the plane was coming. While he still stared, the watcher heard the sound of the motor fade. Complete silence followed.
The man at the dock laughed gruffly. There was no landing place on Death Island; nor was there a field on the mainland anywhere near Lake Marrinack. He saw grief for any aviator who would attempt to bring a ship to earth hereabouts.
When the noise of the motor did not resume, Hildrow’s henchman decided that the plane must have been further away than he supposed. Flying low, it could have passed beyond the wooded stretches of the mainland.
The man’s verdict was completely wrong. The sound that he had heard was closer and higher than he had supposed. In fact, the throb of the motor had ended at a spot one mile above the skull-like cliff at the head of Death Island.
SHROUDED in absolute darkness, an autogyro was settling silently upon the island. With its windmill blades retarding its vertical drop, the ship was responding to the guidance of a master pilot.
Keen eyes were staring downward through the night. The Shadow, in response to the call received through Burbank, was coming to the aid of Professor Arthur Whitburn. Winging northward from a field near New York City, The Shadow had reached his chosen goal.
A clump of blackness in a shiny sheet of black. Such was Death Island, in the center of Lake Marrinack. Nevertheless, The Shadow’s keen eyes had discerned the blotty outline of his objective. With Death Island found, he had picked another mark.
That was the whitened roof of Professor Whitburn’s house. Tall trees held it in darkness during the beginning of The Shadow’s descent. But as he boldly dropped his flying windmill toward the center of the island, The Shadow caught the faint outline of the landing spot he wanted.