sters. 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.

"My God, she's fainted!" he exclaimed.

"I haven't," Laura faltered, trying to open her eyes, "and I'm not going
to, but I think my arm's broken, and my side hurts."

"The fellow's not down here, anyway," Quest declared. "Let's help her
upstairs and get her out of this devil's house."

They supported her up the steps and found a chair for her in the hall. She
was white almost to the lips, but she struggled bravely to keep
consciousness.

"Don't you bother about me," she begged. "Don't let that blackguard go!
You find him. I shall be all right."

The Inspector swung open the telephone cupboard and called for an
ambulance. Then Quest, who had been examining the staircase, suddenly gave
a little exclamation.

"He's done us!" he cried. "Look here, French, this is the original
staircase. There's the leather loop. I know it because there was a crack
on the fourth stair. When we rushed down the cellar after him, he swung
the thing round again and simply walked out of the front door. Damn it,
man, it's open!"

They hurried outside. French blew his whistle. One of the plain-clothes
men came running up from the avenue. He was looking