"Are you who come here of the Brotherhood of the Door?" he asked, apparently repeating a customary challenge.

Campbell answered, his flat voice tremorless. "We are of the Brotherhood."

"Why do you not wear the badge of the Brotherhood, then?"

For answer, the inspector reached in his pocket for the strange emblem and fastened it to his lapel. Ennis did the same.

"Enter, brothers," said the hissing, hooded shape, standing aside to let them pa.s.s.

As they stepped into the tunnel, the hooded guard added in slightly more natural tones, "Brothers, you two are late. You must hurry to get your protective robes, for the ceremony soon begins."

Campbell inclined his head without speaking, and he and Ennis started along the tunnel. Its light, as sourceless as that of the great water-cavern, revealed that it was chiseled from solid rock and that it wound downward.

When they were out of sight of the two hooded guards, Ennis clutched the detective's arm convulsively.

"Campbell," he said, "the ceremony begins soon! We've got to find Ruth first!"

"We'll try," the inspector answered swiftly. "Those hooded robes are apparently issued to all the members to be worn during the ceremony as protection, for some reason, and once we get robes and get them on, Chandra Da.s.s won't be able to spot us.

"Look out!" he added an instant later. "Here's the place where the robes are issued!"

The tunnel had debouched suddenly into a wider s.p.a.ce in which were a group of men. Several were wearing the concealing hoods and robes, and one of these hooded figures was handing out, from a large rack of the robes, three of the garments to three dark Easterners who had apparently entered in the boat just ahead of the cutter.

The three dark Orientals, their faces gleaming with strange fanaticism, quickly donned the robes and hoods and pa.s.sed hurriedly on down the tunnel. At once Campbell and Ennis stepped calmly up to the hooded custodians of the robes, and extended their hands.

One of the hooded figures took down two robes and handed them to them. But suddenly one of the other hooded men spoke sharply.

Instantly all the hooded men but the one who had spoken, with loud cries, threw themselves forward on Campbell and Paul Ennis.

Taken utterly by surprize, the two had no chance to draw their guns. They were smothered by gray-robed men, held helpless before they could move, a half-dozen pistols jammed into their bodies.

Stupefied by the sudden das.h.i.+ng of their hopes, the detective and the young American saw the hooded man who had spoken slowly lift the concealing gray cowl from his face. It was the dark, coldly contemptuous face of Chandra Da.s.s.

4. The Cavern of the Door Chandra Da.s.s spoke, and his strong, vibrant voice held a scorn that was almost pitying.

"It occurred to me that your enterprise might enable you to escape the daggers of my followers, and that you might trail us here," he said. "That is why I waited here to see if you came.

"Search them," he told the other hooded figures. "Take anything that looks like a weapon from them."

Ennis stared, stupefied, as the gray-hooded men obeyed. He was unable to believe entirely in the abrupt reversal of all their hopes, of their desperate attempt.

The hooded men took their pistols from Ennis and Campbell, and even the small gold knife attached to the chain of the inspector's big, old-fas.h.i.+oned gold watch. Then they stepped back, the pistols of two of them leveled at the hearts of the captives.

Chandra Da.s.s had watched impa.s.sively. Ennis, staring dazedly, noted that the Hindoo wore on his breast a different jewel-emblem from the others, a double star instead of a single one.

Ennis' dazed eyes lifted from the blazing badge to the Hindoo's dark face. "Where's Ruth?" he asked a little shrilly, and then his voice cracked and he cried, "You d.a.m.ned fiend, where's my wife?"

"Be comforted, Mr. Ennis," came Chandra Da.s.s' chill voice. "You are going now to join your wife, and to share her fate. You two are going with her and the other sacrifices through the Door when it opens. It is not usual," he added in cold mockery, "for our sacrificial victims to walk directly into our hands. We ordinarily have a more difficult time securing them."

He made a gesture to the two hooded men with pistols, and they ranged themselves close behind Campbell and Ennis.

"We are going to the Cavern of the Door," said the Hindoo. "Inspector Campbell, I know and respect your resourcefulness. Be warned that your slightest attempt to escape means a bullet in your back. You two will march ahead of us," he said, and added mockingly, "Remember, while you live you can cling to the shadow of hope, but if these guns speak, it ends even that shadow."

Ennis and Inspector Campbell, keeping their hands elevated, started at the Hindoo's command down the softly lit rock tunnel. Chandra Da.s.s and the two hooded men with pistols followed.

Ennis saw that the inspector's sagging face was expressionless, and knew that behind that colorless mask, Campbell's brain was racing in an attempt to find a method of escape. For himself, the young American had almost forgotten all else in his eagerness to reach his wife. Whatever happened to Ruth, whatever mysterious horror lay in wait for her and the other victims, he would be there beside her, sharing it!

The tunnel wound a little further downward, then straightened out and ran straight for a considerable length. In this straight section of the rock pa.s.sage, Ennis and Campbell for the first time perceived that the walls of the tunnel bore crowding, deeply chiseled inscriptions. They had not time to read them in pa.s.sing, but Ennis saw that they were in many different languages, and that some of the characters were wholly unfamiliar.

"G.o.d, some of those inscriptions are in Egyptian hieroglyphics!" muttered Inspector Campbell.

The cool voice of Chandra Da.s.s said, behind them, "There are pre-Egyptian inscriptions on these walls, inspector, could you but recognize them, carven in languages that perished from the face of earth before Egypt was born. Yes, back through time, back through mediaeval and Roman and Egyptian and pre-Egyptian ages, the Brotherhood of the Door has existed and has each year gathered in this place to open the Door and wors.h.i.+p with sacrifices They Beyond it."

The fanatic note of unearthly devotion was in his voice now, and Ennis shuddered with a cold not of the tunnel.

As they proceeded, they heard a m.u.f.fled, hoa.r.s.e booming somewhere over their heads, a dull, rhythmic thunder that echoed along the long pa.s.sageway. The walls of the tunnel now were damp and glistening in the sourceless soft light, tiny trickles running down them.

"You hear the ocean over us," came Chandra Da.s.s' voice. "The Cavern of the Door lies several hundred yards out from sh.o.r.e, beneath the rock floor of the sea."

They pa.s.sed the dark mouths of unlit tunnels branching ahead from this illuminated one. Then over the booming of the raging sea above them, there came to Ennis' ears the distant, swelling chant they had heard in the water-cavern above. But now it was louder, nearer. At the sound of it, Chandra Da.s.s quickened their pace.

Suddenly Inspector Campbell stumbled on the slippery rock floor and went down in a heap. Instantly Chandra Da.s.s and his two followers recoiled from them, the two pistols trained on the detective as he scrambled up.

"Do not do that again, inspector," warned the Hindoo in a deadly voice. "All tricks are useless now."

"I couldn't help slipping on this wet floor," complained Inspector Campbell.

"The next time you make a wrong step of any kind, a bullet will smash your spine," Chandra Da.s.s told him. "Quick--march!"

The tunnel turned sharply, turned again. As they rounded the turns, Ennis saw with a sudden electric thrill of hope that Campbell held clutched in his hand, concealed by his sleeve, the heel-hilted knife from his shoe. He had drawn it when he stumbled.

Campbell edged a little closer to the young American as they were hastening onward, and whispered to him, a word at a time.

"Be--ready--to jump--them----"

"But they'll shoot, your first move----" whispered Ennis agonizedly.

Campbell did not answer. But Ennis sensed the detective's body tautening.

They came to another turn, the strong, swelling chant coming loud from ahead. They started around that turn.

Then Inspector Campbell acted. He whirled as though on a pivot, the heel-knife flas.h.i.+ng toward the men behind them.

Shots coughed from the pistols that were pressed almost against his stomach. His body jerked as the bullets struck it, yet he remained erect, his knife stabbing with lightning rapidity.

One of the hooded men slumped down with a pierced throat, and as Campbell sprang at the other, Ennis desperately launched himself at Chandra Da.s.s. He bore the Hindoo from his feet, but it was as though he was fighting a demon. Inside his gray robe, Chandra Da.s.s writhed with fiendish strength.

Ennis could not hold him, the Hindoo's body seeming of spring-steel. He rolled over, dashed the young American to the floor, and leaped up, his dark face and great black eyes blazing.

Then, half-way erect, he suddenly crumpled, the fire in his eyes dulling, a call for help smothered on his lips. He fell on his face, and Ennis saw that the heel-knife was stuck in his back. Inspector Campbell jerked it out, and put it back into his shoe. And now Ennis, staggering up, saw that Campbell had knifed the two hooded guards and that they lay in a dead heap.

"Campbell!" cried the American, gripping the detective's arm. "They've wounded you--I saw them shoot you."

Campbell's bruised face grinned briefly. "Nothing of the kind," he said, and tapped the soiled gray vest he wore beneath his coat. "Chandra Da.s.s didn't know this vest is bullet-proof."

He darted an alert glance up and down the lighted tunnel. "We can't stay here or let these bodies lie here. They may be discovered at any moment."

"Listen!" said Ennis, turning.

The chanting from ahead swelled down the tunnel, louder than at any time yet, waxing and waxing, reaching a triumphant crescendo, then again dying away.

"Campbell, they're going on with the ceremony now!" Ennis cried. "Ruth!"

The detective's desperate glance fastened on the dark mouth of one of the branching tunnels, a little ahead.

"That side tunnel--we'll pull the bodies in there!" he exclaimed.

Taking the pistols of the dead men for themselves, they rapidly dragged the three bodies into the darkness of the unlit branching tunnel.

"Quick, on with two of these robes," rasped Inspector Campbell. "They'll give us a little better chance."

Hastily Ennis jerked the gray robe and hood from Chandra Da.s.s' dead body and donned it, while Campbell struggled into one of the others. In the robes and concealing hoods, they could not be told from any other two members of the Brotherhood, except that the badge on Ennis' breast was the double star instead of the single one.

Ennis then spun toward the main, lighted tunnel, Campbell close behind him. They recoiled suddenly into the darkness of the branching way, as they heard hurrying steps out in the lighted pa.s.sage. Flattened in the darkness against the wall, they saw several of the gray-hooded members of the Brotherhood hasten past them from above, hurrying toward the gathering-place.

"The guards and robe-issuers we saw above!" Campbell said quickly when they were pa.s.sed. "Come on, now."

He and Ennis slipped out into the lighted tunnel and hastened along it after the others.

Boom of thundering ocean over their heads and rising and falling of the tremendous chanting ahead filled their ears as they hurried around the last turns of the tunnel. The pa.s.sage widened, and ahead they saw a ma.s.sive rock portal through whose opening they glimpsed an immense, lighted s.p.a.ce.

Campbell and Ennis, two comparatively tiny gray-hooded figures, hastened through the mighty portal. Then they stopped. Ennis felt frozen with the dazing shock of it. He heard the detective whisper fiercely beside him.

"It's the Cavern, all right--the Cavern of the Door!"

They looked across a colossal rock chamber hollowed out beneath the floor of ocean. It was elliptical in shape, three hundred feet by its longer axis. Its black basalt sides, towering, rough-hewn walls, rose sheer and supported the rock ceiling which was the ocean floor, a hundred feet over their heads.

This mighty cathedral hewn from inside the rock of earth was lit by a soft, white, sourceless light like that in the main tunnel. Upon the floor of the cavern, in regular rows across it, stood hundreds on hundreds of human figures, all gray-robed and gray-hooded, all with their backs to Campbell and Ennis, looking across the cavern to its farther end. At that farther end was a flat dais of black basalt upon which stood five hooded men, four wearing the blazing double-star on their b.r.e.a.s.t.s, the fifth, a triple-star. Two of them stood beside a cubical, weird-looking gray metal mechanism from which upreared a spherical web of countless fine wires, unthinkably intricate in their network, many of them pulsing with glowing force. The sourceless light of the cavern and the tunnel seemed to pulse from that weird mechanism.

Up from that machine, if machine it was, soared the black basalt wall of that end of the cavern. But there above the gray mechanism the rough wall had been carved with a great, smooth facet, a giant, gleaming black oval face as smooth as though planed and polished. Only, at the middle of the glistening black oval face, were carven deeply four large and wholly unfamiliar characters. As Ennis and Campbell stared frozenly across the awe-inspiring place, sound swelled from the hundreds of throats. A slow, rising chant, it climbed and climbed until the basalt roof above seemed to quiver to it, cras.h.i.+ng out with stupendous effect, a weird litany in an unknown tongue. Then it began to fall.

Ennis clutched the inspector's gray-robed arm. "Where's Ruth?" he whispered frantically. "I don't see any prisoners."

"They must be somewhere here," Campbell said swiftly. "Listen----"

As the chant died to silence, on the dais at the farther end of the cavern the hooded man who wore the triple-jeweled star stepped forward and spoke. His deep, heavy voice rolled out and echoed across the cavern, flung back and forth from wall to rocky wall.

"Brothers of the Door," he said, "we meet again here in the Cavern of the Door this year, as for ten thousand years past our forefathers have met here to wors.h.i.+p They Beyond the Door, and bring them the sacrifices They love.

"A hundred centuries have gone by since first They Beyond the Door sent their wisdom through the barrier between their universe and ours, a barrier which even They could not open from their side, but which their wisdom taught our fathers how to open.

"Each year since then have we opened the Door which They taught us how to build. Each year we have brought them sacrifices. And in return They have given us of their wisdom and power. They have taught us things that lie hidden from other men, and They have given us powers that other men have not.

"Now again comes the time appointed for the opening of the Door. In their universe on the other side of it, They are waiting now to take the sacrifices which we have procured for them. The hour strikes, so let the sacrifices be brought."

As though at a signal, from a small opening at one side of the cavern a triple file of marchers entered. A file of hooded gray members of the Brotherhood flanked on either side a line of men and women who did not wear the hoods or robes. They were thirty or forty in number. These men and women were of almost all races and cla.s.ses, but all of them walked stiffly, mechanically, staring ahead with unseeing, distended eyes, like living corpses.

"Drugged!" came Campbell's shaken voice. "They're all drugged, and don't know what is going on."

Ennis' eyes fastened on a small, slender girl with chestnut hair who walked at the end of the line, a girl in a straight tan dress, whose face was white, stiff, like those of the others.

"There's Ruth!" he exclaimed frantically, his cry m.u.f.fled by his hood.

He plunged in that direction, but Campbell held him back.

"No!" rasped the inspector. "You can't help her by simply getting yourself captured!"

"I can at least go with her!" Ennis exclaimed. "Let me go!"

Inspector Campbell's iron grip held him. "Wait, Ennis!" said the detective. "You've no chance that way. That robe of Chandra Da.s.s' you're wearing has a double-star badge like those of the men up there on the dais. That means that as Chandra Da.s.s you're ent.i.tled to be up there with them. Go up there and take your place as though you were Chandra Da.s.s--with the hood on, they can't tell the difference. I'll slip around to that side door out of which they brought the prisoners. It must connect with the tunnels, and it's not far from the dais. When I fire my pistol from there, you grab your wife and try to get to that door with her. If you can do it, we'll have a chance to get up through the tunnels and escape."

Ennis wrung the inspector's hand. Then, without further reply, he walked boldly with measured steps up the main aisle of the cavern, through the gray ranks to the dais. He stepped up onto it, his heart racing. The chief priest, he of the triple-star, gave him only a glance, as of annoyance at his lateness. Ennis saw Campbell's gray figure slipping round to the side door.

The gray-hooded hundreds before him had paid no attention to either of them. Their attention was utterly, eagerly, fixed upon the stiff-moving prisoners now being marched up onto the dais. Ennis saw Ruth pa.s.s him, her white face an unfamiliar, staring mask.

The prisoners were ranged at the back of the dais, just beneath the great, gleaming black oval facet. The guards stepped back from them, and they remained standing stiffly there. Ennis edged a little toward Ruth, who stood at the end of that line of stiff figures. As he moved imperceptibly closer to her, he saw the two priests beside the gray mechanism reaching toward knurled k.n.o.bs of ebonite affixed to its side, beneath the spherical web of pulsing wires.

The chief priest, at the front of the dais, raised his hands. His voice rolled out, heavy, commanding, reverberating again through all the cavern.

5. The Door Opens "Where leads the Door?" rolled the chief priest's voice.

Back up to him came the reply of hundreds of voices, m.u.f.fled by the hoods but loud, echoing to the roof of the cavern in a thunderous response.

"It leads outside our world!"

The chief priest waited until the echoes died before his deep voice rolled on in the ritual.

"Who taught our forefathers to open the Door?"

Ennis, edging desperately closer and closer to the line of victims, felt the mighty response reverberate about him.

"They Beyond the Door taught them!"

Now Ennis was apart from the other priests on the dais, within a few yards of the captives, of the small figure of Ruth.