"The quartet is now complete," the metallic voice of Foxhound continued.

"In a moment, I intend to flood this chamber with water. You happen to be below the level of the lake and the water will fill every inch of your tomb. You have my permission to swim upward with it until you reach the ceiling. After that, use your own judgment. I am sorry to have to drown you, but you four happen to be the last persons on earth who menace my safety!"

"At least tell us who you are, before you kill us!" Cardona cried, thickly.

"I thought you knew. I am Foxhound!"

The jeering laughter that accompanied the remark was utterly devoid of pity. The plate in the ceiling closed.

Cardona whirled toward Doctor Hanson and Madge. "In Heaven's name, who is he? Kelsea?"

"I don't know," Hanson gasped. "I've never seen him except when he was wearing his silver-gray disguise."

The Shadow clutched Cardona's arm with an urgent gesture. He had dropped to his knees beside the heavy chunk of iron ore. He held his left wrist and forearm against the rock, gestured to Cardona, to make him fast to the heavy weight. A vision of death was bright in Cardona's bulging eyes, but he clenched his teeth and obeyed the strange demand of The Shadow.

He was none too soon. A scream of terror came from Madge Payne. The plate in the floor was rising!

Water bubbled and spurted. The water was under terrific pressure. Itjetted upward as the plate rose higher and higher. It filled the room with a sullen thunder, splashing and foaming over the stone floor like a millrace.

The Shadow and Cardona were bent over, the chunk of ore to which The Shadow's left wrist and forearm were now fettered. Both men lifted the weight, their faces flushed with the strain. They staggered through foaming water toward the spouting column that jetted through the manhole in the floor.

Barely able to hold its weight, they half dragged, half carried, the ore chunk between them.

Hanson and Madge stared at them with tragic, hopeless eyes. She and the doctor were in each other's arms, waiting for a death they were certain was inevitable.

The Shadow knelt beside the manhole and Cardona let go his support of the rock. It dropped straight through the foaming pillar of water, dragging The Shadow headlong after it. His legs shot stiffly upward and vanished from sight.

THE SHADOW was in the slanting pipe through which the water of the lake was roaring upward under pressure! But he was going down, down, dragged by the terrific weight of the iron ore, past the rushing tug of the water. In no other way could he have possibly pa.s.sed counter to that streaming torrent. He had counted on it, banked upon it with his life - and his calculation was working!

His lungs were expanded to their full limit, filled with every atom of air they could hold. He needed it, bubbled it out, sparingly from between tightly compressed lips like a miser. He felt the pressure decrease and his descent become faster. He was out of the pipe and into the lake itself. An instant later, he struck soft mud and lay motionless on the bottom.

His free hand slashed viciously with a knife and cut his bound arm loose.

He began to move - but sidewise, rather than upward. He knew what this peril was. The suction of the undersurface torrent was whirling him back to the opening of the pipe.

He fought away from this danger by muscular kicks of his legs and a fierce cupped motion of his upraised hands. The suction diminished, ceased. He began to shoot toward the surface of the lake. Just as his lungs were bursting with the agony of depleted oxygen, his head splashed into view above the lake. He drew in a long, shuddering breath.

But his exertions became, if anything, more desperate. Turning, he swam with all speed to the concrete edge of the lake. He emerged dripping on the sh.o.r.e. Not more than three minutes had elapsed from the moment he had left the death chamber, unknown to the wily Foxhound.

He ran down the steep declivity of the sh.o.r.e. He knew that every instant counted, if he were to save the victims trapped behind the locked steel door.

They were rising swiftly toward the ceiling on the foaming crest of the flood.

When the water reached the closed ceiling - THE SHADOW ran straight for the iron-runged ladder that led upward in the darkness along a deep fissure in the cavern wall. Wriggling through a hinged opening at the top of his climb, he found himself in a stone gallery that led inward and then curved sharply to the left.

Another opening, then strong light dazzled his eyes. He was in the room directly above the murder vault. He saw the closed metal plate through which the voice of Foxhound had issued. Beyond it were two motionless figures sprawled on the floor. Masked; robed in black. They were dead, both of them. They had been shot through the head. The Shadow ripped the masks from their faces. A woman and a man. The man was Stoner. The woman was Helene.

The disclosure did not appear to surprise The Shadow. He had wasted barely a second in that swift unmasking. Now he sprang toward the closed manhole and swung it open.

The surface of foaming water was barely a foot below his eyes. He saw Cardona swimming desperately, his mouth wide agape almost under the circular opening in the ceiling. Beyond Cardona were the splashing heads of Madge and Doctor Hanson. They yelled with bubbling shouts, as they saw the deep-socketed eyes of The Shadow, his robed arm bending to clutch at them.

He caught Madge's arm, hauled her through. He was reaching for Cardona when Madge screamed shrilly behind his crouched body. The Shadow whirled. A masked figure in a doorway behind him sent a scarlet streak of flame from the muzzle of a steady pistol.

The slug tore into The Shadow's body, toppling him. Lying weakly on his side, he saw the killer - black-robed, masked, silent - pull the trigger again.

There was no time for him to move.

It was Madge who acted promptly. She had scooped a fallen gun from the floor with almost one motion. She threw it with desperate haste, straight at the masked face of the murderer. Instinctively, his hand rose to ward off the flying missile, and his shot went wide of The Shadow's p.r.o.ne body. The next instant, The Shadow was on his feet and Joe Cardona was rising through the manhole; Doctor Hanson followed him.

The masked man fled. Cardona and The Shadow were after him in an instant, the latter reeling as he ran. The chase led through a stone corridor. For a moment, The Shadow faltered, and Cardona pa.s.sed him with flying strides.

There was a gun in Joe's hand. He reached a solid oaken door a scant second behind his quarry. The fugitive tried to slam the door, but Joe was too fast.

He leaped into a large room, and there sounded instantly the roar of a pistol. The Shadow followed in time to see the masked man fall with a neat, round hole in his covered forehead. Accurate shooting was one of Cardona's police specialties.

Joe knelt, ripped the mask from the dead man. It was Alonzo Kelsea.

"I THOUGHT so!" Cardona cried. "So Kelsea was Foxhound, after all!"

The Shadow laughed faintly. There was pain in his glazed eyes and a trickle of blood from a bullet wound in the right side of his chest.

He said, "Yes," in a peculiar voice. It seemed extraordinarily loud. But as he said it he shook his head negatively, and his finger rested for an instant across his lips. He pointed silently toward the closed door of what appeared to be a large closet.

An expression of amazement pa.s.sed across Cardona's tense face. He had unmasked Kelsea with a growl of certainty. Death, he thought, had narrowed down his suspects to the sinister ident.i.ty of the lawyer. He knew now that Madge and Doctor Hanson were innocent cat's-paws in this conspiracy. Stoner and the blond Helene were dead. That left only Kelsea.

But The Shadow had shaken his head, pointed warningly toward the closed door of the closet. Was Foxhound really still alive - cornered and desperate?

Cardona advanced quietly toward the closet door, his gun ready to spill lead through the panel. His face was stiff, watchful. He suspected that the closet was probably a concealed a.r.s.enal. Foxhound would not have fled there so stupidly unless he had some method of turning the tables on his foes at thelast minute.

No sound came from the closet.

A rich rug on the floor covered the sound of Joe's advancing feet. But as he stepped in front of the door, he felt the rug sink slightly under his weight and a hidden bell clanged.

Instantly, The Shadow's hand tugged fiercely at his companion. Cardona was dragged heavily backward, fell flat to the floor. Beside him lay the crouched figure of The Shadow.

Hardly had the two men dropped when the closet echoed with the stuttering roar of a concealed machine gun. Holes made a grim, dancing pattern in the wood of the door. The plastered wall opposite spat rhythmic flicks of white dust.

Cardona, breathless at the sudden murderous ambush, lay where he had fallen, his pistol finger paralyzed. But The Shadow's twin guns went into prompt, purposeful action. He fired at the pattern of holes in the door. Every bullet he loosed thudded through the barrier within a six-inch circle.

From within, came a shrill, shuddering cry. The clamor of the machine gun ceased.

A voice cried in thin terror: "Don't shoot! I surrender!"

Joe was on his feet. He took a prudent step backward. So did The Shadow.

Both of them suspected treachery. That too-easy surrender sounded phony.

"Come out!" Joe yelled. "Hands high above your head! One funny move and we'll cut you down!"

THE door opened slowly. A masked figure emerged. Joe gave a quick cry of wonder, but The Shadow was silent. The figure was silver-gray from head to foot; and oddly menacing, in spite of the fact that its clenched hands were lifted obediently above the hooded head.

Cardona took a single step forward and halted as a hard, reckless laugh came from behind the fluttering silken mask of Foxhound.

"Be careful, gentlemen! I'm holding a live grenade in my left hand, and the pin has been drawn! You understand the situation?"

The metallic voice became slow, very distinct in this ornate, magnificently furnished living room deep in the heart of an abandoned mine.

"I intend not to be caught. My purpose is to walk peacefully from this room, locking both of you behind me. If you obey, you lose a prisoner but you will save your lives. Otherwise, I shall throw the grenade and blow all three of us to chunks of b.l.o.o.d.y flesh!"

There was truth in Foxhound's voice, a tense desperation in his poised body. He knew the game was up and was willing to stake everything on one suicidal gamble.

"Agreed!" The Shadow rasped. A flick of his burning eyes ordered Joe Cardona to back up toward a far corner of the room.

Joe obeyed. He had caught a revealing glimpse of The Shadow's momentarily averted face. The lips had moved briefly. They framed a silent word: "Talk!"

Joe talked desperately from his corner. He threatened, cajoled, pleaded.

Foxhound listened, laughing faintly as he turned slightly and began to edge toward the door. The Shadow estimated the positions of Cardona, of the closet and Foxhound.

He leaped without warning, dropping both guns.

AS The Shadow sprang, Foxhound snarled and threw the live grenade. The Shadow's fist crashed against his chest, sending him reeling. At the same instant he bent, s.n.a.t.c.hed the corrugated steel egg from the rug, and flipped it backward in a straight line over his shoulder. His aim was bulletlike, and accurate. The grenade vanished through the doorway of the open closet. Foxhound was still falling from The Shadow's blow when the closet flamed with a terrific explosion.

Chunks of jagged metal whizzed across the room. The Shadow's face flicked suddenly crimson, as though a knife had been drawn crookedly across his cheek.

Foxhound screamed and collapsed, rolling headlong on the rug. He had been exactly in line with the closet door. A fragment of metal had pierced his thigh, ripping through flesh, shattering the bone.

Cardona, who was out of range of death in the far corner, leaped forward.

There was nothing for him to do. The Shadow had solved the desperate dilemma in less than five seconds.

Blood poured from the gash across his cheek, but he paid no attention to the wound, or to the slug from Alonzo Kelsea's gun that was imbedded deep within his body. His hand stayed Cardona's eager rush. Into Cardona's ear he spoke quietly the name of a dead man.

"What? But he's - dead! How could a dead man -"

Incredulous, dazed by the knowledge The Shadow had just imparted to him, Cardona dropped to one knee and unmasked the prisoner. The Shadow's prediction was true.

Cardona was staring into the pinched, sneering face of Charles Malone, known as the brother of the detective murdered on the America-Gaul Line pier!

From the corridor beyond the room came two soaking-wet figures. They peered like frightened ghosts. Doctor Hanson and Madge. They were unaware of anything except the unmasked criminal on the floor. Like Cardona, they both cried out with amazement.

"But Malone was murdered, cut to pieces by an airplane propeller at Newark Airport!"

THE SHADOW smiled. His voice was weak, but his words were crystal clear.

Malone had been the executioner, not the victim. His cunning hand had driven the airplane. The victim - a penniless derelict hired for the purpose - had been dressed in Malone's clothes, his pockets filled with Malone's papers and belongings to mislead the police.

The Shadow had guessed the truth, because of the bizarre method of the crime. An airplane propeller, a victim ripped to b.l.o.o.d.y tatters - all this to prevent a true identification of an unfortunate derelict lured by a few dollars to a treacherous slaughter.

The Shadow's s.p.a.ced words linked the triple personality together. "Thomas Springer - Foxhound - Charles Malone!"

Malone jeered shrilly, "Prove it! Malone, yes; Foxhound, yes; but I'm not Springer, and you never can prove it or find the twenty million dollars stolen from the Investment Trust Co.!"

The Shadow didn't reply. He walked across the richly furnished room toward the wall. There was a picture on that wall - a painting of a gorgeously proportioned dog, a foxhound. He jerked the painting from the wall. His knife ripped the canvas away. Under the canvas was another picture - the missing master-piece of Remy Colette! The long-vanished "Landscape with Flowers!"

Foxhound snarled with helpless rage as Cardona snapped handcuffs on his jerking wrists. The Shadow, oblivious to the drama behind him, was peeling a strip of canvas away from the Colette. There were two backs to the painting, a real and a false. Pasted in orderly array was the absolute, the d.a.m.ning proof gathered in Europe by the murdered Herbert Backus.

Photos of Thomas Springer stolen from the files of a French plastic surgeon, both before and after his facial transformation; a list of every foreign bank where credits had been established by the wily Foxhound; hisaliases used successfully to deceive the police of a half dozen countries.

There was not a fact nor a doc.u.ment missing. Jimmy Dawson had hidden the stolen evidence in the one place where Foxhound had never dreamed of looking.

Foxhound's own headquarters!

Pale, his face smeared with blood, The Shadow laughed. The name Foxhound itself had been the first key to the truth. "Run with the fox and hunt with the hounds!" Cardona's friend - Cardona's deadly enemy. Only Charles Malone fitted that description. His reckless pun had tipped his cleverly hidden ident.i.ty to the keen intelligence of The Shadow.

CHAPTER XXIV.

A GIFT FOR CARDONA.

DOCTOR HANSON and Madge Payne stood like frozen ghosts, staring at the slumped figure of the captured criminal. They were unaware that Cardona and The Shadow had withdrawn to the side of the room, were seated close together on the rich upholstery of an expensive couch. The Shadow was wounded, desperately tired, but his lips moved in a steady murmur. It was necessary for the police to have the complete facts in the case.

Cardona listened, his face rigid with attention. There was only one gap in the facts: the motives and the actions of Madge and Doctor Hanson.

Cardona rose from the sofa. He approached the white-faced couple across the room, and accused them: "You were both in Leland Payne's home on the night of his death. You've said that you didn't murder him, and now I believe you. He was killed by Stoner and Helene Carfax, the latter disguised as a man."

Cardona's voice hardened. "Why were you there - and why didn't you notify the police, instead of hiding the truth?"

Hanson's face was very pale, but there was no evasion in his words. With his arm protectingly around Madge's slender shoulders, he explained.

He was in love with Madge, wanted to marry her. But Leland Payne hated him for his political opinions. Payne decided to get rid of him by offering him

ten.

thousand dollars to give up his niece. That was why Hanson and the girl had been present in the old man's mansion on that tragic night.

They found Payne murdered and a message involving Hanson scrawled in his diary. Payne had discovered that his courtroom testimony for Jimmy Dawson was false. The visitor who had called on him at the exact time that Dawson was actually killing Backus and Pat Malone at the pier of the America-Gaul Line was an impostor, cunningly disguised by a facial surgeon.