some of the characters were wholly unfamiliar.
“God, some of those inscriptions are in Egyptian hieroglyphics!” muttered Inspector Campbell.
The cool voice of Chandra Dass 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 mediæval 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 worship 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 muffled, hoarse booming somewhere over their heads, a dull, rhythmic thunder that echoed along the long passageway. 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 Dass’ voice. “The Cavern of the Door lies several hundred yards out from shore, beneath the rock floor of the sea.”
They passed 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 Dass quickened their pace.
Suddenly Inspector Campbell stumbled on the slippery rock floor and went down in a heap. Instantly Chandra Dass 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 Dass 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 flashing 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 Dass. He bore the Hindoo from his feet, but it was as though he was fighting a demon. Inside his gray robe, Chandra Dass 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 Dass 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 Dass’ 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 passage. 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 passed. “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 passage widened, and ahead they saw a massive rock portal through whose opening they glimpsed an immense, lighted space.
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 breasts, 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,