Quest smiled at him derisively.

“Get up,” he ordered.

Very slowly Craig obeyed him.  He was a pitiful-looking object, but a single look into Quest’s face showed him the folly of any sort of appeal.

“Walk out of the room,” Quest ordered, “in front of me—­so!  Now, then, turn to the right and go down the stairs.”

They all gave a little cry as they saw him appear, a trembling, pitiful creature, glancing around like a trapped animal.  He commenced to descend the stairs, holding tightly to the banisters.  Quest remained on the landing above, his revolver in his hand.  French waited in the hall below, also armed.  Laura gripped Lenora’s arm in excitement.

“They’ve got him now!” she exclaimed.  “Got him, sure!”

On the fourth or fifth stair, Craig hesitated.  He suddenly saw the Professor standing below.  He gripped the banisters with one hand.  The other he flung out in a threatening gesture.

“You’ve given me away to these bloodhounds!” he cried,—­“you, for whom I have toiled and slaved, whom I have followed all over the world, whom I have served faithfully with the last breath of my body and the last drop of blood in my veins!  You have brought them here—­tracked me down!  You!”

The Professor shook his head sorrowfully.

“Craig,” he said, “you have been the best servant man ever had.  If you are innocent of these crimes, you can clear yourself.  If you are guilty, a dog’s death is none too good for you.”

Craig seemed to sway for a moment upon his feet.  Only Lenora, from the hall, saw that he was fitting his right foot into what seemed to be a leather loop hanging from the banisters.  Then a wild shout of surprise broke from the lips of all of them, followed by a moment of stupefied wonder.  The whole staircase suddenly began to revolve.  Craig, clinging to the banisters, disappeared.  In a moment or two there was a fresh click.  Another set of stairs, almost identical to the first, had taken their place.

“The cellar!” Quest shouted, as he rushed down the stairs.  “Quick!”

They wrenched open the wooden door and hurried down the dark steps into the gloomy, unlit cellar.  The place was crowded with packing-cases, and two large wine barrels stood in the corner.  At the farther end was a door.  Quest rushed for it and stood on guard.  A moment later, however, he called to Laura and pressed his revolver into her hand.

“Stand here,” he ordered.  “Shoot him if he tries to run out.  I’ll search in the packing-cases.  He might be dangerous.”

The Professor, out of breath, was leaning against one of the pillars, his arm passed around it for support.  Lenora, with Quest and French, searched hastily amongst the packing-cases.  Suddenly there was a loud crack, the sound of falling masonry, followed by a scream from Laura.  French, with a roar of anger, rushed towards her.  She was lying on her side, already half covered by falling bricks and masonry.  He dragged her away, just in time.