Dimly there whispered to them, as though from a distance and through great walls, a swelling sound of chanting. As they listened, hearts beating rapidly, a square of the rock wall of the cavern abruptly flew open beside them, as though hinged like a door. Inside it was the mouth of a soft-lit, man-high tunnel, and in its opening stood two men. They wore over their clothing shroud-like, loose-hanging robes of gray, asbestos-like material. They wore hoods of the same gray stuff over their heads, pierced with slits at the eyes and mouth. And each wore on his breast the blazing star-badge.
Through the eye-slits the eyes of the two surveyed Campbell and Ennis as they halted, transfixed by the sudden apparition. Then one of the hooded men spoke measuredly in a hissing, Mongolian voice.
"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 pass.
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.