"Very, my dear; very damp indeed," was the Sister's answer. "I think we had better not stay; I am shivering with the cold air; and there's nothing, as you perceive, to see." The ear-trumpet had been left behind, and Mary Ursula did not dare raise her voice to a loud key. She was inwardly shivering herself; not with the chilly, mildewy air, but with her own involuntary thoughts. Thoughts that she would have willingly forbidden entrance to, but could not. With these secret vaults and places under the Keep, secret because they were not generally known abroad, what facilities existed for dealing ill with Anthony Castlemaine; for putting him out of sight for ever! "Can he be concealed here still, alive or dead?" she murmured to herself. "Surely not alive: for how----" A sound! A sound close at hand. It was on the opposite side of the vault, and was like the striking of some metal against the wall: or it might have been the banging of a door. Instinctively Mary Ursula hid the lantern under her cloak, caught hold of Sister Mildred, and crouched down with her behind the remotest pillar. The Sister had heard nothing, of course; but she comprehended that there was some cause for alarm. "Oh, my dear, what will become of us!" she breathed. "Whatever is it?" Mary dared not speak. She put her hand on the Sister's lips to enjoin silence, and kept it there. Sister Mildred had gone down in a most uncomfortable position, one leg bent under her; and but for grasping the pillar for support with both hands she must have tumbled backwards. Mary Ursula, was kneeling in very close contact, which helped to prop the poor lady up behind. As to the pillar, it was nothing like wide enough to conceal them both had the place been light. But it was pitch dark. A darkness that might almost be felt. In the midst of it; in the midst of their painful suspense, not knowing what to expect or fear, there arose a faint, distant glimmering of light over in the direction where Mary had heard the sound. A minute afterwards some indistinct, shadowy form appeared, dressed in a monk's habit and cowl. It was the apparition of the Grey Friar. A low, unearthly moan broke from Sister Mildred. Mary Ursula, herself faint with terror, as must be confessed, but keenly alive to the necessity for their keeping still and silent, pressed the Sister's mouth more closely, and strove to reassure her by clasping her waist with the other hand. The figure, holding its lamp before it, glided swiftly across the vault amid the pillars, and vanished. It all seemed to pass in a single moment. The unfortunate ladies--"distilled almost to jelly with the effect of fear," as Horatio says--cowered together, not knowing what was next to happen to them, or what other sight might appear. Sister Mildred went into an ague-fit.