She cowered back in the chair, and the man beside her, strong-nerved though he was, shuddered uncontrollably. For staring down on them from above, with his face pressed against the glass, was Hubert Garling. He was crawling over the smooth surface like some loathsome insect—gloating as he watched them. Moved by an uncontrollable impulse, Jack Denver seized his discarded shoe and hurled it at the madman. So straight was the aim that they could see him start back; then, as the shoe dropped harmlessly back to the floor, Garling’s face once more pressed against the glass. And he was shaking with maniacal laughter. “Turn off the light, dear,” sobbed the girl. “I can’t bear it.” There was a click and the tower was in darkness. “Hold me in your arms, darling,” she cried, pitifully. “I’m not frightened when you’ve got me close.” Jack Denver took her in his arms almost mechanically: into his mind had come an idea. Above them, outlined against the sky, they could see Garling, and it seemed as if he was beating furiously against the glass with his fists, enraged at being baulked of his triumph. “Listen, sweetheart,” said Jack, urgently. “There’s a chance. Just a chance. If he thinks we’re dead it’s possible he might come in and open the door. I want you to sprawl forward on the floor—face downwards. Don’t move. Just lie there. Then I’ll switch on the light, stagger round the room once or twice, and then fall myself. Act, my beloved, act as you have never acted before.” “I understand, dear,” she answered, steadily. “Just kiss me once more.” He strained her to him; then she lay down on the floor half hidden by the desk. “Ready, Hilda?” “Yes, Jack; I’m ready.” Once more the light went on, and Jack Denver stared upwards. Act—oh, God!—let him act sufficiently to deceive the madman. He plucked at his collar, and staggered wildly back against the desk; then he raised imploring hands to Garling. His breath came in short gasps; he went to the door and beat on it. Then again he raised his hands towards the gibbering, gloating face, transformed now with a sort of a diabolical ecstasy into something utterly fiendish. Then he pitched forward on his face—turned over, and lay staring through half-closed eyes at the man above. Had they bluffed him? Garling’s face was still pressed against the glass; his eyes roamed from one to the other of his victims. A quarter of an hour—eternity—went by, and he was still there. And then quite suddenly he was gone; the stars shone through the dome clear and unimpeded. For five minutes Jack Denver remained motionless; then, still lying in the same position, he spoke in a whisper. “He’s gone, darling; but don’t move yet. If he comes in, I’ll go for him, but whatever happens you get on the other side of the door.” “All right, Jack; but pray Heaven he comes soon. I don’t think I can go on much longer.”