UPPER Broadway was in a turmoil. Police whistles sounded. The sirens of fire trucks cleaved the air.

Thousands of persons had been startled by the explosion that had wrecked the interior of the old apartment house. Police cordons were forming to keep back the excited crowd.

Joe Cardona was at work. He had recovered from the dazzling flares which had temporarily blinded him.

Inspector Timothy Klein was on the scene. He had followed the detective, and had arrived just after the explosion. Now he was commenting on the situation.

“It’s lucky you got out, Joe,” he said. “Otherwise, we’d never have got the dope on this. Seven of them you say—”

“Six,” corrected Cardona. “We got one, you know.”

“One’s not enough!”

“Our men are in the streets.”

A fire ladder had been raised against the side of the old apartment house. Smoke was pouring through the doors and windows. Cardona, awaiting the report of his men, paused to watch a fireman who was ascending the ladder. The task was a perilous one.

The wall was in danger of cracking, yet the man appeared unperturbed. He reached the top of the ladder and peered into the ruins beneath, as one would look into the crater of a smoldering volcano.

Then he gazed downward to the street. Other firemen were following him. The man at the top of the ladder laughed softly as he stepped from the ladder and stood upon the dizzy parapet.

Strangely enough, his eyes were not focused upon the ruins of the inner building. He was staring toward the roofs of the houses in the surrounding blocks.

His comrades were arriving. He made a last careful survey. His eye detected a small, dark trapdoor in the roof of a house across the street. Then his gaze followed along an entire block to a spot at the most distant corner.

The firemen were training a hose upon the blaze in the depths of the burning building. The man who had led the way suddenly stepped back upon the ladder and descended to the street. He became one of the many firemen who were working about the engines. Then he disappeared.

A moment later, some one tapped Detective Cardona upon the shoulder. Both the detective and the inspector turned to see a fireman in uniform. They did not recognize him as the man whom they had seen upon the ladder.

“You’re looking for the guys that started this, aren’t you?” asked the fireman.

“Yeah,” said Cardona. “What about it?”

“Across the street,” said the fireman, making a gesture with his thumb. “There’s a trapdoor in the roof. Right over the hock shop. Looked to me like it moved. Maybe—”

“Get your men!” exclaimed Klein to Cardona.

As the detective and the inspector left, the fireman laughed softly to himself. He ignored his apparent duty as he walked away from the crowd and disappeared around the corner.

THE pawnshop designated by the fireman was closed. There was a locked door beside it that led to a flight of stairs. Cardona ordered three of his men to smash it.

Uniformed policemen pushed back the curious persons who were invading the side street, wondering what this new activity might mean.

The detectives broke down the door. They found a passageway beside the steps. As Cardona was urging his men to preserve quiet, one of his assistants approached him. The man had gone down the passage.

“Looks like there’s a way downstairs here,” he said.

“A passage under the street!” exclaimed Cardona. “Maybe that’s it!”

He looked quickly about him and picked out three detectives.

“Find the way back!” he ordered. “Maybe some of them are trapped. But the rest of us are going up!”

The intrepid detective led the way. He and his men stole softly up the stairs. They paused to listen after they had gone three flights.

Cardona, his flashlight turned to the floor, hissed a command for silence. He fancied that he had heard a slight sound from above. Then he was sure of it. There was a distinct thump of a trapdoor being dropped.

“Come on, men!” exclaimed Cardona. “After them!”

The detectives rushed up the last flight. Cardona’s light revealed a trapdoor which was moving. Some one was trying to force it into place.

The detective did not hesitate. He fired his automatic through the barrier. The trapdoor no longer moved.

Lifted by two of his men, Cardona pushed it up and peered out upon the roof. The huddled form of a man lay in front of him.

Then came a revolver shot. A bullet splintered the trapdoor. Joe Cardona ducked. Then he put his hand through the opening and fired in the direction of the shots. There was no volley in return.

The detective and his men emerged upon the roof. Crouching in the darkness, they gazed in all directions.

They could see no one.

Then came a shout from the building across the street. Firemen on top of the burning apartment house had heard the shots. They were signaling. One of them pointed in the distance.

“Come on!”

It was Cardona’s command. He started the pursuit over the irregular roofs, leaving one of his men to search the victim who had been killed by the shots through the trapdoor.

Clambering over a small wall between two buildings, Cardona sighted his quarry. Five men were making their way across the roofs. Two of them were leaning upon the others.

CARDONA’S revolver spoke. His shots went wide. The five men scattered. Each one dropped to the roof. They seemed to be seeking safety.

With a shout of triumph, Cardona leaped from the wall, and his men followed.

Then came the answering fire. The members of the Silent Seven shot with deadly aim. Two of Cardona’s men fell.

“Behind the wall!” screamed Cardona. His cry was too late. There were five men with him; all had come forward. Two were out of the fight. The others fired with their automatics.

Answering shots came from the enemy. Another of Cardona’s men gasped and collapsed.

Cardona raised himself to fire. A shot came from across the roof. The detective’s arm dropped helplessly as a bullet struck his wrist.

The odds were against the detectives. Cardona realized that. The merciless survivors of the Silent Seven were about to exterminate the detectives. There was no hope.

Cardona saw a hooded figure rise boldly, by the edge of the roof. He knew that he was the man’s target; and he was helpless. His eyes were staring. Then he heard the report of a revolver.

He thought the hooded man had fired.To his amazement, the man toppled and plunged headlong from the roof of the building!

Then Cardona saw who had fired. Another man had appeared, through an opening close by the spot where the last of the Seven were grouped. Standing like an avenging specter, this newcomer had shot the man whose gun was trained upon the helpless detective!

“The Shadow!” exclaimed Cardona. “The Shadow!”

Four hooded men arose as one. They were the last of the Silent Seven. With one accord, they hurled themselves at the man who blocked their path to safety. The Shadow’s gun spoke again and again and again. His enemies went down — all but one.

The last man flung himself upon The Shadow. For a moment they grappled. Then Cardona saw The Shadow fall, perilously near the edge of the roof. Neither he nor his opponent fired.

The last man of the Silent Seven threw himself once more against The Shadow, who seemed to topple over the edge. Without waiting, the robed man dashed to the opening in the roof, to make his escape.

Vengeance filled Cardona’s mind. He was helpless. He could only cry out in anger. One of his detectives responded.

The sound of shots came close beside Cardona. He fancied that he saw the robed figure tremble and sway as it went swiftly through the opening in the roof.

Cardona arose. Forgetful of his own wound, he hurried forward to the spot where he had last seen The Shadow. There was a wall straight down to the street. It was studded with windows. There was no sign of The Shadow.

A limousine started along the street and turned the corner. Cardona realized that it was taking the escaping man to safety; that it contained the grim fighter who had overcome The Shadow!

His conjecture was correct. In the limousine speeding toward Broadway, a stern-faced man sat muttering in the darkness of the back seat. He had thrown his robe from his shoulders. Each passing street light revealed the features of a middle-aged man whose face bore a long, narrow scar.

A VOICE spoke in the darkness. Its tones were a low, harsh whisper, that were heard only by the man in back. The chauffeur could not hear the voice. The glass partition between him and the back barred the sound.

The man with the scarred face turned in amazement to see a stranger whose black cloak and broad-brimmed hat made him almost invisible.

“So,” said the voice. “I have the pleasure of being with Professor Marvin Jukes. You, I take it, are the leader of the Silent Seven.”

The grim-faced man tightened his lips.

“A man of high standing — to the public,” came the ironical tones of the sinister voice. “But at heart a criminal — the leader of a gang of criminals!”

There was no reply.

“The Silent Seven,” repeated the voice, hissing the words. “Each member kept a reminder of his duty. Like Marchand’s dice. Always the number seven. There were seven. Now there is only one the last of the Seven!”

“Who are you?” demanded the man with the scarred face.

“They call me The Shadow,” came the reply. “You thought that I no longer existed — after our struggle on the roof. But I am used to walls, professor. When I go down them, I do not fall. You left me too soon. I came down and found your limousine awaiting you.”

“What do you want of me?”

“You know my purpose.” The Shadow’s voice was significant. “You have captured one of my men. He is in danger. You alone know where he is. I offer you your life in exchange for his. Tell me where he is!”

The leader of the Seven did not reply. He was staring straight ahead, as though he did not hear The Shadow’s words.

“Will you answer me?” came the whispered voice.

“Yes,” replied Jukes slowly. “This is my answer.”

His hand had crept to a pocket in the side of the car. Now he swung his body around and thrust an automatic toward The Shadow.

But Jukes had not reckoned on the alertness of that strange man in black. A viselike grip caught his wrist.

Try as he might, Jukes could not carry the few inches that were necessary to aim it toward The Shadow.

The men locked in a grim struggle. Jukes was determined to kill this enemy — the only man who had ever thwarted the machinations of the Silent Seven. With a quick twist he wrenched free.

Before he could swing the gun into play, a sudden expression of anguish appeared upon his face. He slumped back into the corner of the car. He pressed his hand against his side.

The parting shots fired by Cardona’s plain-clothes man had not been in vain. The wounds which Jukes had received had spelled his doom, although he had at first been almost oblivious to them.

His urge to kill The Shadow had sustained him despite his serious condition. Now, his strength was sagging. The Shadow plucked the gun from his hand and held it before his eyes.

“Answer me!” hissed The Shadow. “Answer me — or die!”

An ugly leering smile came over the features of Professor Jukes. Even in this last moment, the evil leader of the Silent Seven gloated in triumph.

He did not fear The Shadow. A new enemy was conquering him, and that enemy was death. His head dropped forward. A sighing gasp came from his lips. His hands fell to his side.

The Shadow leaned over the leader of the Silent Seven. He placed his hand against the man’s forehead.

The car stopped before a traffic light.

The Shadow opened the door and slipped silently to the street. The limousine moved onward, carrying the dead body of Professor Jukes, and The Shadow’s hope of rescuing Harry Vincent!