"Miss Byrne can choose," she continued. "Either she swears not to say a word till we are both safe away, or else we can shut her in the dungeon of the castle. I know where it is, in the wall of this tower. She will never be found there, and I can take her food from time to time till I am ready to join you. Isn't that a good plan?" Mark considered. "I don't think we will give her the option of swearing not to tell," he said presently. "As if I would ever promise such a thing!" Juliet interrupted, indignant. "But," he went on, ignoring this outburst, "otherwise I think your idea is good. Where is this dungeon? We may be disturbed at any minute, and enough time has been wasted already." "I will go first and show the way," said Julia. "I have an electric torch," and she stepped into the clock and lowered herself through the trap-door. Mark motioned to Juliet to follow. "Ladies first," he said with a sneer. Juliet turned and made a dash for the door. "I won't go! I won't! I won't!" she cried desperately, though in her heart she knew she could not resist if he chose to use force. Perhaps if she screamed, some one would hear. Oh, where was Gimblet? Why did he leave her to the mercy of these people? "Help! Help!" She lifted up her voice and shrieked as loud as she could. With a vicious scowl Mark sprang upon her, and clapped a hand over her mouth. Then, as she still continued to produce muffled sounds of distress, he stuffed his handkerchief in between her teeth and, lifting her bodily in his arms, thrust her before him into the clock, and pushed her roughly down the hidden stair. Half-way down she lost her footing, and fell to the bottom, where Julia was standing with her little lamp in her hand. Mark was following close behind, and between them they picked her up and hurried her, limping and bruised, along the narrow passage. She was allowed to take the handkerchief out of her mouth, for no cry could penetrate the immense thickness of these blocks of stone. At the point where there was a break to right and left in the walls of the passage, Julia came to a standstill. "Here it is," she said, turning her light on to the opening in the wall on the left-hand side. "The door is gone, so you will have to fetch something to block it up with." It seemed to be a small, cell-like chamber, built into the side of the tower. It may have contained a dozen cubic yards of space, and had neither door nor window. "There are some slabs of stone at the end of the passage," said Julia. "They are heavy, but you are strong, you will be able to bring them. We must leave a little space at the top of the door to admit some air, and for me to pass food through to our prisoner." She laughed with a feverish merriment. "It will be like feeding the animals at the Zoo," she said. Mark signified his approval by a nod. "And is this the way?" he asked, turning round and starting off in the opposite direction.