“I’m not going to give this to any detective,” he said quietly, tapping the piece of paper in his hand.

Dale’s heart pounded sickeningly but she kept her courage up.

“What do you mean?” she said fiercely.  “What are you going to do?”

He faced her across the fireplace, his airy manner coming back to him just enough to add an additional touch of the sinister to the cold self-revelation of his words.

“Let us suppose a few things, Miss Ogden,” he said.  “Suppose my price is a million dollars.  Suppose I need money very badly and my uncle has left me a house containing that amount in cash.  Suppose I choose to consider that that money is mine—­then it wouldn’t be hard to suppose, would it, that I’d make a pretty sincere attempt to get away with it?”

Dale summoned all her fortitude.

“If you go out of this room with that paper I’ll scream for help!” she said defiantly.

Fleming made a little mock-bow of courtesy.  He smiled.

“To carry on our little game of supposing,” he said easily, “suppose there is a detective in this house—­and that, if I were cornered, I should tell him where to lay his hands on Jack Bailey.  Do you suppose you would scream?”

Dale’s hands dropped, powerless, at her sides.  If only she hadn’t told him—­too late!—­she was helpless.  She could not call the detective without ruining Jack—­and yet, if Fleming escaped with the money—­how could Jack ever prove his innocence?

Fleming watched her for an instant, smiling.  Then, seeing she made no move, he darted hastily toward the double doors of the alcove, flung them open, seemed about to dash up the alcove stairs.  The sight of him escaping with the only existing clue to the hidden room galvanized Dale into action.  She followed him, hurriedly snatching up Miss Cornelia’s revolver from the table as she did so, in a last gesture of desperation.

“No!  No!  Give it to me!  Give it to me!” and she sprang after him, clutching the revolver.  He waited for her on the bottom step of the stairs, the slight smile still on his face.

Panting breaths in the darkness of the alcove—­a short, furious scuffle—­he had wrested the revolver away from her, but in doing so had unguarded the precious blue-print—­she snatched at it desperately, tearing most of it away, leaving only a corner in his hand.  He swore—­tried to get it back—­she jerked away.

Then suddenly a bright shaft of light split the darkness of the alcove stairs like a sword, a spot of brilliance centered on Fleming’s face like the glare of a flashlight focused from above by an invisible hand.  For an instant it revealed him—­his features distorted with fury—­about to rush down the stairs again and attack the trembling girl at their foot.

A single shot rang out.  For a second, the fury on Fleming’s face seemed to change to a strange look of bewilderment and surprise.