But Anderson was not to be caught napping again.  “Wells!” he barked.  The Doctor stopped and turned.

“Where were you when she was locked in this room?”

The Doctor’s eyes sought the floor—­the walls—­wildly—­for any possible loophole of escape.

“I didn’t shut her in if that’s what you mean!” he said defiantly.  “There was someone shut in there with her!” He gestured at the Hidden Room.  “Ask these people here.”

Miss Cornelia caught him up at once.

“The fact remains, Doctor,” she said, her voice cold with anger, “that we left her here alone.  When we came back you were here.  The corridor door was locked, and she was in that room—­ unconscious!”

She moved forward to throw the light of her candle on the Hidden Room as the detective passed into it, gave it a swift professional glance, and stepped out again.  But she had not finished her story by any means.

“As we opened that door,” she continued to the detective, tapping the false mantel, “the Doctor deliberately extinguished our only candle!”

“Do you know who was in that room?” queried the detective fiercely, wheeling on the Doctor.

But the latter had evidently made up his mind to cling stubbornly to a policy of complete denial.

“No,” he said sullenly.  “I didn’t put out the candle.  It fell.  And I didn’t lock that door into the hall.  I found it locked!”

A sigh of relief from Bailey now centered everyone’s attention on himself and Dale.  At last the girl was recovering from the shock of her terrible experience and regaining consciousness.  Her eyelids fluttered, closed again, opened once more.  She tried to sit up, weakly, clinging to Bailey’s shoulder.  The color returned to her cheeks, the stupor left her eyes.

She gave the Hidden Room a hunted little glance and then shuddered violently.

“Please close that awful door,” she said in a tremulous voice.  “I don’t want to see it again.”

The detective went silently to close the iron doors.  “What happened to you?  Can’t you remember?” faltered Bailey, on his knees at her side.

The shadow of an old terror lay on the girl’s face, “I was in here alone in the dark,” she began slowly—­“Then, as I looked at the doorway there, I saw there was somebody there.  He came in and closed the door.  I didn’t know what to do, so I slipped in—­there, and after a while I knew he was coming in too, for he couldn’t get out.  Then I must have fainted.”

“There was nothing about the figure that you recognized?”

“No.  Nothing.”

“But we know it was the Bat,” put in Miss Cornelia.  The detective laughed sardonically.  The old duel of opposing theories between the two seemed about to recommence.

“Still harping on the Bat!” he said, with a little sneer, Miss Cornelia stuck to her guns.

“I have every reason to believe that the Bat is in this house,” she said.