One night after Stuart Bruxton's experience in Greenhurst, Harry Vincent encountered developments in Philadelphia.

From the darkened window of a small apartment, he was peering across a narrow courtyard to a lighted room in a wing of the same building. The window of that room was open.

Harry was watching Denby Chadwick.

A sound came across the court. It was the ringing of a telephone. Harry was awaiting it as eagerly as Chadwick. He looked at the luminous dial of his wrist watch. It registered twenty minutes of eleven. Chadwick was answering the telephone.

"Yes — yes" — were his words — "I understand. I've been waiting to hear from you. I don't like it, though… I'm afraid I'll lose everything… You're demanding too much… No — no" — the voice had a pathetic note "don't say that… Wait… Wait a moment." Chadwick left the phone and came to the window. He stared out into the court with haggard eyes. His hands moved restlessly, clasping and unclasping. He drew down the sash.

Unable to hear more, Harry left his apartment and hastened through the hall. It was a considerable distance to the door of Chadwick's apartment.

Arriving there, Harry found himself in luck. The transom of Chadwick's door was slightly open. Harry could hear the voice within, although the words were not so plain as they had been in the room across the court.

Harry realized that he had missed an important part of Chadwick's conversation, and he chided himself for not having come here the moment that the phone call had commenced. It was too late for such regrets, however.

"I understand," Harry heard Chadwick say. "I've got to come through" — the voice was glum — "and you're letting me off easy, after all. I want to be sure that this is all of it, though." A pause followed, indicating that Chadwick was listening from the other end. Then came these words:

"I'll be there, then. But I want to be sure that I'll be safe. You know I'm taking a chance, going alone. I can't do anything else, but — " The voice stopped, as though the speaker might be listening to an interruption from the other end.

When Chadwick spoke again, it was with the tone of a man who has been somewhat reassured.

"You're protecting me positively, then. Well, I'll be there. I know the way. Midnight."

The conversation ended. Harry Vincent hurried back toward his own apartment. He waited behind a corner until he saw young Chadwick appear and start for the elevator. Then Harry descended by the stairway.

Chadwick was leaving the lobby when Harry reached the ground floor. Harry knew his immediate destination. Chadwick's car was outside the apartment.

The man was driving away when Harry reached the street and clambered into his own coupe. He saw the taillight of Chadwick's car as it turned a corner. Harry followed in pursuit.

Chadwick's car reached a trafficked street. It was not difficult to trail it.

Harry was thinking deeply as he kept pace behind the car in front. He knew something of Chadwick's troubles, but not enough.

So far as his uncle's death was concerned, Chadwick had a perfect alibi. But the fact that he had been quizzed so closely by the county detective made it appear as though there might be a plot against him. Blackmail was afoot, Harry decided. Perhaps old Grant Chadwick had been killed because he would not meet demands. Perhaps the heritage which Denby Chadwick had received was putting him in hot water also.

Harry remembered the fiendish plan that had operated against Stuart Bruxton. If the same men were after Denby Chadwick, there would certainly be danger.

Chadwick was going to a meeting. Harry, armed, was following him. The meeting was to be at midnight. It must be some distance away.

Harry's surmise was justified when Chadwick headed along the boulevard toward New York; then turned off to the right.

This gave his plan away. Chadwick was evidently aiming for the Palmyra bridge, a long span that connected Pennsylvania with New Jersey.

They reached the bridge, and after following Chadwick to the other side, Harry allowed the man to increase the space that separated the two cars. There was a straight road ahead; it would not do to be too close.

Far out in the country, Chadwick speeded his machine and drew out of sight around a long bend. When Harry reached the straight stretch that followed the curve, he could see no sign of his quarry. But his headlights showed a crossroads. There had been a heavy rain, and a smeared tire track indicated that a car had turned to the left.

Harry swung in that direction. He was piqued at his failure to follow effectively; but now he had a hunch that he believed must be correct.

They had been traveling for nearly an hour. Chadwick had shown only a few bursts of speed. The destination must be close, otherwise the man would have traveled more rapidly.

Harry knew this road, now that he was upon it. Three miles ahead was located a roadhouse called the Green Mill — a spot where beer runners sometimes gathered. Harry was convinced that the lonely roadhouse was Denby Chadwick's destination.

At ten minutes of twelve, Harry neared the Green Mill. He piloted his coupe up a side road; then ran it into an unfenced field beneath a clump of trees. The tires wallowed in mud, but the car slid through to a dry spot.

There was no time to waste. Harry could see the lights of the roadhouse. He opened the back of his coupe. He lifted an inner lid to disclose a complete and compact wireless sending set.

Harry strung an aerial between two trees. He worked with speed and precision.

The sending key clicked when he had completed operations. Harry's fingers were at work. With the special equipment provided him by The Shadow, Harry was reporting.

Somewhere, not far from New York, The Shadow had a sending station which enabled him to keep in direct touch by wireless. Harry had used this method of communication in the past. So far as he knew, the man at the other end was Burbank, The Shadow's most trusted agent.

Harry had often communicated with him.

Harry did not wait for a response. Satisfied that the set was working, he hurried toward the roadhouse, and did not slacken his pace until he was close by the building. There, he crouched in darkness and wormed his way toward a lighted window.

The shade was drawn, but there was a slight space at the bottom. Peering through, Harry saw Denby Chadwick, seated at a table.

Chadwick was waiting for someone who had not yet arrived. While Harry watched and waited, he heard a car pull in from the pike, bound toward a parking space at the side of the roadhouse. A few minutes later, a door opened within the room. A man entered. Harry stared.

The man was heavy and powerfully built. His face was an ugly one.

Stuart Bruxton's description of Grady flashed through Harry's mind. He felt positive this man was the killer who had slain both Jefferson and Powell!

Harry's hand tightened on his automatic. If Grady attempted murder here, he would fail.

Harry was ready to send a bullet through the man's brain if he attacked Denby Chadwick.

But it became evident that Grady was here for no such purpose. His face was ugly and leering; but it carried no fiendish look.

The men were conversing, but Harry could not catch their words. Chadwick drew forth a small portfolio, and gave it to Grady. The evil-faced man opened it and peered in at the contents.

He spoke a few words to Chadwick; then arose and went to the door.

For a moment Harry thought he was leaving; instead, he reappeared with a waiter. The man had bottles and glasses. Drinks were poured.

Grady, grinning, imbibed deeply. Chadwick, morose, did not touch his glass. This was an opportunity. Harry felt that nothing would occur for several minutes at least. He hurried back to the spot where he had rigged his aerial.

He had removed the sending apparatus about thirty feet from the car. Opening communication, he tapped a code message, telling all that he had observed, and giving his exact location. He received a prompt response. He was to watch what happened, and to wait until the men left; then to follow Grady in preference to Chadwick.

Most important, Harry was to send a quick signal by wireless before he left, leaving the equipment set up, if necessary, to make a hasty departure.

Gauging the distance from the spot to the roadhouse, Harry figured he could make a quick trip back and forth. He tapped word to stand by; that he would signal again within five minutes. Leaving the key, he went back to the Green Mill.

Chadwick and Grady were still at their table. Harry watched them a few minutes.

Chadwick swallowed his drink and rose to leave. Harry slid away from the window, and headed toward the coupe. He knew that if Chadwick should be going home, he would pass by the little road that led in from the Pike. At his car, Harry stood listening. Hearing no sound of an automobile, he decided to send word to Burbank. He turned to go to the sending set.

As he stepped away from the coupe, a man leaped upon him!

Harry had no opportunity to seize his automatic. The gun was in his pocket, for he had expected no trouble back here at the car.

He realized, now, that he had been followed from the roadhouse on this last trip. He was resolved to defeat this enemy.

Fighting furiously, Harry broke free and dealt the man a powerful punch on the jaw. The fellow staggered, and Harry leaned forward to deliver another telling blow.

At that instant, another figure rose from beside him. Harry saw a descending arm. He turned quickly to ward off the falling blow.

A solid object struck the side of Harry's head. The Shadow's operative sank with a groan.

Half stunned, he was incapable of motion as he felt himself gripped by both antagonists. Expert hands bound him. A handkerchief was thrust in his mouth and its ends tied behind his head.

Harry was lifted bodily and thrust in the front seat of his own car.

In a daze, he heard an automobile starting from the roadhouse. A few minutes later, the sound was repeated. Harry's mind barely managed to grasp the fact that both Chadwick and Grady were now gone from the Green Mill.

Who, then, were these men who had captured him?

More minutes dragged by. The door on the other side of the car opened. One of the captors entered the coupe and took the wheel. The starter buzzed and the car moved slowly backward, sloughing; through the mud toward the side road.

Harry Vincent, a helpless victim, was being taken to an unknown destination — and the only clue to his capture was the silent key upon the sending apparatus that he had left amid the trees!

Unseen danger had come to Harry — before he had been able to signal that he expected trouble!