“You little cat!” he exclaimed.  “We’ll see the thing through, then.  You are prisoners here just as much as though you were in the vault.”

Forrest, who had spoken very little, came suddenly forward.

“We have talked too much,” he said, “and wasted too much time.  Let us have the issue before us in black and white.  Engleton, are you well enough to understand what I say?”

“Perfectly,” Engleton answered.  “Go on.”

“Will you sign a retraction of your charges against us, and pledge your word of honour never to repeat them, or to make any complaint, formal or otherwise, as to your detention here.”

“I’m d——­d if I will!” Engleton answered.

“Consider what your refusal means first,” Forrest said.  “Open the passage door, Cecil.”

Cecil pushed it back, and a little breath of the noxious odour stole into the room.

“You either make us that promise, Engleton,” he said, “or as sure as I’m standing here, we’ll drag you both down that passage, right to the end, and throw you into the sea.”

“And hang for it afterwards,” Engleton said, with a sneer.

“Not we,” Forrest declared.  “The currents down there are strange ones, and it would be many weeks before your bodies were recovered.  Your character in London is pretty well known, and Kate here has been seen often enough on her way up to the Hall.  People will soon put two and two together.  There are a dozen places in the Spinney where one could slip off into the sea.  Besides we shall have a little evidence to offer.  Oh, there is nothing for us to fear, I can assure you.  Now then.  I can see it’s no use arguing with you any longer.”

“One moment,” Kate said.  “What about the young lady I left outside?”

Cecil turned upon her swiftly.

“Don’t tell lies, Kate,” he said.  “It’s a poor sort of tale that.”

“At any rate it’s no lie,” Kate answered.  “When I came to your front door, I left the young lady who was staying here only a few weeks ago, Miss Le Mesurier you called her, sitting in the barn waiting.”

Cecil laughed scornfully.

“Did she drop from the clouds?” he asked.

“She has been staying at the farm,” Kate answered, “for days.  I brought her with me to-night because I thought that she might know something about Lord Ronald’s disappearance.  She is there waiting.  If I do not return by daylight, she will go to the police.”

“I think,” Forrest remarked ironically, “that we will risk the young lady outside.  Your story, my dear, is ingenious, but scarcely plausible.  If you are ready, Cecil—­”

The four of them were suddenly stupefied into a dead silence.  Their eyes were riveted upon the door which led to the underground passage.  Cecil’s face was almost grotesque with the terrible writing of fear.  Distinctly they could all hear footsteps stumbling along the uneven way.  Forrest was first to recover the power of speech.  He called out to Cecil from the other end of the room.