en it came
doubling back, and Estelle, with dismay, saw the cat rush across the
glade, and into the summer-house. In another moment Bootles had
followed. Terrified lest the dog should be shut in, and heedless of her
own danger, she ran down the steps and into the forbidden room, in the
vain hope of catching the dog, and rescuing him before the door closed.

No one was near to see what happened. In her fear she ran on without
looking where she was going. Round and round, dodging from this corner
to that, flew the cat, the dog after it; presently they both plunged
into the black cavernous place Georgie had seen. Feeling her way with
both hands, Estelle ran after them, calling to Bootles. The light behind
was growing fainter, the way before her was shrouded in the darkness of
night. Frightened at last, she stopped, and at that moment there was a
crash which shook the whole building. With a terror, which made her cold
and sick, she realised that the terrible door had shut. She was
imprisoned, and no one knew it!

* * * * *

Meantime, Alan and Marjorie had set off with the intention of going
straight to the Smuggler's Hole, and on into the cave passage. But,
passing through the wilderness, close to the rear of the rampart, which
here jutted out to some distance beyond the ruined summer-house, they
both fancied they heard sounds in the brushwood. It turned out to be
only a stray cat, but it had the effect of diverting them from their
purpose for a time, since the animal seemed scared. Alan decided it was
running away from something, and as a bird also flew past at the moment,
he determined to make investigations.

Followed by Marjorie, he clambered down into a sort of dry ditch, the
remains of the old moat. Though overgrown with ivy and brambles, it
would be easier walking than forcing his way through the dense
underwood, and they would make far less noise. Without even a whispered
word, the brother and sister crept cautiously along, coming at length to
an open, but small glen. Up to this point they had had no difficulty;
but here the ditch was closed by a stout hedge, made still stronger by
faggots and barbed wire. This was unexpected, for there appeared to be
no reason for such a protection, and Alan and Marjorie sat on the bank
to consider what that hedge was intended to conceal. The mossy glen was
behind them, and all around was the deep silence of the woods. In front
towered the grey, c