Adam, leaving his wife free to follow her own desires with regard to Lilla and her grandfather, busied himself with filling the well-hole with the fine sand prepared for the purpose, taking care to have lowered at stated intervals quantities of the store of dynamite, so as to be ready for the final explosion. He had under his immediate supervision a corps of workmen, and was assisted by Sir Nathaniel, who had come over for the purpose, and all were now staying at Lesser Hill. Mr. Salton, too, showed much interest in the job, and was constantly coming in and out, nothing escaping his observation. Since her marriage to Adam and their coming to stay at Doom Tower, Mimi had been fettered by fear of the horrible monster at Diana's Grove. But now she dreaded it no longer. She accepted the fact of its assuming at will the form of Lady Arabella. She had still to tax and upbraid her for her part in the unhappiness which had been wrought on Lilla, and for her share in causing her death. One evening, when Mimi entered her own room, she went to the window and threw an eager look round the whole circle of sight. A single glance satisfied her that the White Worm in _propria persona_ was not visible. So she sat down in the window-seat and enjoyed the pleasure of a full view, from which she had been so long cut off. The maid who waited on her had told her that Mr. Salton had not yet returned home, so she felt free to enjoy the luxury of peace and quiet. As she looked out of the window, she saw something thin and white move along the avenue. She thought she recognised the figure of Lady Arabella, and instinctively drew back behind the curtain. When she had ascertained, by peeping out several times, that the lady had not seen her, she watched more carefully, all her instinctive hatred flooding back at the sight of her. Lady Arabella was moving swiftly and stealthily, looking back and around her at intervals, as if she feared to be followed. This gave Mimi an idea that she was up to no good, so she determined to seize the occasion for watching her in more detail. Hastily putting on a dark cloak and hat, she ran downstairs and out into the avenue. Lady Arabella had moved, but the sheen of her white dress was still to be seen among the young oaks around the gateway. Keeping in shadow, Mimi followed, taking care not to come so close as to awake the other's suspicion, and watched her quarry pass along the road in the direction of Castra Regis.