"Somers!" she called, very softly. Getting no reply, she peered into the room and then very cautiously came inside it. A startled exclamation, quickly suppressed, escaped her at sight of the empty bed, and she drew back and glanced hastily over her shoulder. Gathering courage from the continued stillness, she went over to the bureau and fumbled in one of the drawers. Something fell from her hand--from Trenholm's position he could not see what, and he dared not move--and she struck a match. Shielding it in her hand, she stooped over. She remained so long in that position that Trenholm grew alarmed; then, with a swiftness and stealth which left him breathless, she was gone. Had Betty taken the thirteenth letter? Trenholm was on edge, but, before he dared venture out, another figure stood in the doorway, and by the light from the hall lamp, he recognized Miriam. Without hesitation she went at once to the bureau and opening the second drawer took out one of Mrs. Nash's scarfs. Would she see the envelope and, thinking it had accidentally fallen in the dustpan, pick it up? Or was it not there for her to pick up? Trenholm heaved a sigh of thankfulness when Miriam turned and went into the hall. A stealthy step inside the bedroom a few seconds later caused Trenholm again to draw back into the shelter of the screen in time to miss being seen by Corbin. The caretaker had advanced only a few paces when a hand was laid on his shoulder and he was jerked back. "_Sacré Dieu!_ What do you in my mistress' bedroom, _cochon_?" hissed Pierre in his ear. What answer the terrified man would have made was checked by Alexander Nash's voice in the hall. "Pierre, bring the car around!" Nash failed to see the two men, chauffeur and caretaker, steal out of his wife's doorway, for he turned at the moment to address Alan Mason--only to find that the young man had disappeared. Nash hesitated for a fraction of a second, then tiptoed down the hall. Trenholm's sensitive ears caught the creak of a floor board, and the faint "seep--seep" of something being dragged across the floor. A flood of light from an electric torch half blinded him, accustomed to the almost total darkness of the room, and he rubbed his eyes to clear his vision, just as the light was focused full upon the dustpan. The thirteenth letter stood out in bold relief. The light was dimmed instantly and again Trenholm caught the sound of something creeping across the floor. The light flared up again with unexpected swiftness and Trenholm saw a shapeless figure, its head and shoulders enveloped in some black garment, squatting over the dustpan. The torch lay at rest by it, and Trenholm had a glimpse of long, slender fingers holding the letter as he crept from behind the screen and as noiseless as the shadows about him, reached the kneeling figure. The stamped envelope was held in one hand and in the other was a perforation gauge--