“Fresh candle grease!  Now who do you suppose did that?  Do you remember how Mr. Gillette, in Sherlock Holmes, when he—­”

Her voice trailed off.  She stooped and followed the trail of the candle grease away from the window, ingeniously trying to copy the shrewd, piercing gaze of Mr. Gillette as she remembered him in his most famous role.

“It leads straight to the fireplace!” she murmured in tones of Sherlockian gravity.  Bailey repressed an involuntary smile.  But her next words gave him genuine food for thought.

She stared at the mantel of the fireplace accusingly.  “It’s been going through my mind for the last few minutes that no chimney flue runs up this side of the house!” she said.

Bailey stared.  “Then why the fireplace?”

“That’s what I’m going to find out!” said the spinster grimly.  She started to rap the mantel, testing it for secret springs.

“Jack!  Jack!” It was Dale’s voice, low and cautious, coming from the landing of the stairs.

Bailey stepped to the door of the trunk room.

“Come in,” he called in reply.  “And shut the door behind you.”

Dale entered, turning the key in the lock behind her.

“Where are the others?”

“They’re still searching the house.  There’s no sign of anybody.”

“They haven’t found—­Mr. Anderson?”

Dale shook her head.  “Not yet.”

She turned toward her aunt.  Miss Cornelia had begun to enjoy herself once more.

Rapping on the mantelpiece, poking and pressing various corners and sections of the mantel itself, she remembered all the detective stories she had ever read and thought, with a sniff of scorn, that she could better them.  There were always sliding panels and hidden drawers in detective stories and the detective discovered them by rapping just as she was doing, and listening for a hollow sound in answer.  She rapped on the wall above the mantel—­exactly—­there was the hollow echo she wanted.

“Hollow as Lizzie’s head!” she said triumphantly.  The fireplace was obviously not what it seemed, there must be a space behind it unaccounted for in the building plans.  Now what was the next step detectives always took?  Oh, yes—­they looked for panels; panels that moved.  And when one shoved them away there was a button or something.  She pushed and pressed and finally something did move.  It was the mantelpiece itself, false grate and all, which began to swing out into the room, revealing behind a dark, hollow cubbyhole, some six feet by six—­the Hidden Room at last!

“Oh, Jack, be careful!” breathed Dale as her lover took Miss Cornelia’s candle and moved toward the dark hiding-place.  But her eyes had already caught the outlines of a tall iron safe in the gloom and in spite of her fears, her lips formed a wordless cry of victory.

But Jack Bailey said nothing at all.  One glance had shown him that the safe was empty.