“Come in,” began Miss Cornelia.  “Sit down.”  He obeyed both commands docilely enough.

“Are you better now?”

“Somewhat.”  His words still came very slowly.

“Billy—­you can go.”

“I stay, please!” said Billy wistfully, making no movement to leave.  His gesture toward the darkness of the corridor spoke louder than words.

Bailey watched him, suspicion dawning in his eyes.  He could not account for the butler’s inexplicable terror of being left alone.

“Anderson intimated that the Doctor had an accomplice in this house,” he said, crossing to Billy and taking him by the arm.  “Why isn’t this the man?” Billy cringed away.  “Please, no,” he begged pitifully.

Bailey turned him around so that he faced the Hidden Room.

“Did you know that room was there?” he questioned, his doubts still unquieted.

Billy shook his head.

“No.”

“He couldn’t have locked us in,” said Miss Cornelia.  “He was with us.”

Bailey demurred, not to her remark itself, but to its implication of Billy’s entire innocence.

“He may know who did it.  Do you?”

Billy still shook his head.

Bailey remained unconvinced.

“Who did you see at the head of the small staircase?” he queried imperatively.  “Now we’re through with nonsense; I want the truth!”

Billy shivered.

“See face—­that’s all,” he brought out at last.

“Whose face?”

Again it was evident that Billy knew or thought he knew more than he was willing to tell.

“Don’t know,” he said with obvious untruth, looking down at the floor.

“Never mind, Billy,” cut in Miss Cornelia.  To her mind questioning Billy was wasting time.  She looked at the Unknown.

“Solve the mystery of this man and we may get at the facts,” she said in accents of conviction.

As Bailey turned toward her questioningly, Billy attempted to steal silently out of the door, apparently preferring any fears that might lurk in the darkness of the corridor to a further grilling on the subject of whom or what he had seen on the alcove stairs.  But Bailey caught the movement out of the tail of his eye.

“You stay here,” he commanded.  Billy stood frozen.  Beresford raised the candle so that it cast its light full in the Unknown’s face.

“This chap claims to have lost his memory,” he said dubiously.  “I suppose a blow on the head might do that, I don’t know.”

“I wish somebody would knock me on the head!  I’d like to forget a few things!” moaned Lizzie, but the interruption went unregarded.

“Don’t you even know your name?” queried Miss Cornelia of the Unknown.

The Unknown shook his head with a slow, laborious gesture.

“Not—­yet.”

“Or where you came from?”

Once more the battered head made its movement of negation.