ut a yard square in front of them, which had
something the look of a brick fireplace, a fireplace raised about two
feet from the ground. But, save for one row of bricks in front, the
floor of it was emptiness. Antony took a torch from his pocket and
flashed it down into the blackness.

"Look," he whispered to the eager Bill. "The steps begin down there. Six
feet down."

He flashed his torch up again. There was a handhold of iron, a sort of
large iron staple, in the bricks in front of them.

"You swing off from there," said Bill. "At least, I suppose you do. I
wonder how Ruth Norris liked doing it."

"Cayley helped her, I should think.... It's funny."

"Shall I go first?" asked Bill, obviously longing to do so. Antony shook
his head with a smile.

"I think I will, if you don't mind very much, Bill. Just in case."

"In case of what?"

"Well in case."

Bill, had to be content with that, but he was too much excited to wonder
what Antony meant.

"Righto," he said. "Go on."

"Well, we'll just make sure we can get back again, first. It really
wouldn't be fair on the Inspector if we got stuck down here for the rest
of our lives. He's got enough to do trying to find Mark, but if he has
to find you and me as well--"

"We can always get out at the other end."

"Well, we're not certain yet. I think I'd better just go down and back.
I promise faithfully not to explore."

"Right you are."

Antony sat down on the ledge of bricks, swung his feet over, and sat
there for a moment, his legs dangling. He flashed his torch into the
darkness again, so as to make sure where the steps began; then returned
it to his pocket, seized the staple in front of him and swung himself
down. His feet touched the steps beneath him, and he let go.

"Is it all right?" said Bill anxiously.

"All right. I'll just go down to the bottom of the steps and back. Stay
there."

The light shone down by his feet. His head began to disappear. For
a little while Bill, craning down the opening, could still see faint
splashes of light, and could hear slow uncertain footsteps; for a little
longer he could fancy that he saw and heard them; then he was alone....

Well, not quite alone. There was a sudden voice in the hall outside.

"Good Lord!" said Bill, turning round with a start, "Cayley!"

If he was not so quick in thought as Antony, he was quick enough in
action. Thought was not demanded now. To close the secret door safely
but noiselessly, to