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.