Mimi was greatly distressed when she saw her cousin lying prone. She had a few times in her life seen Lilla on the verge of fainting, but never senseless; and now she was frightened. She threw herself on her knees beside Lilla, and tried, by rubbing her hands and other measures commonly known, to restore her. But all her efforts were unavailing. Lilla still lay white and senseless. In fact, each moment she looked worse; her breast, that had been heaving with the stress, became still, and the pallor of her face grew like marble.

At these succeeding changes Mimi's fright grew, till it altogether mastered her. She succeeded in controlling herself only to the extent that she did not scream.

Lady Arabella had followed Caswall, when he had recovered sufficiently to get up and walk--though stumblingly--in the direction of Castra Regis. When Mimi was quite alone with Lilla and the need for effort had ceased, she felt weak and trembled. In her own mind, she attributed it to a sudden change in the weather--it was momentarily becoming apparent that a storm was coming on.

She raised Lilla's head and laid it on her warm young breast, but all in vain. The cold of the white features thrilled through her, and she utterly collapsed when it was borne in on her that Lilla had passed away.

The dusk gradually deepened and the shades of evening closed in, but Mimi did not seem to notice or to care. She sat on the floor with her arms round the body of the girl whom she loved. Darker and blacker grew the sky as the coming storm and the closing night joined forces. Still she sat on--alone--tearless--unable to think. Mimi did not know how long she sat there. Though it seemed to her that ages had passed, it could not have been more than half-an-hour. She suddenly came to herself, and was surprised to find that her grandfather had not returned. For a while she lay quiet, thinking of the immediate past. Lilla's hand was still in hers, and to her surprise it was still warm. Somehow this helped her consciousness, and without any special act of will she stood up. She lit a lamp and looked at her cousin. There was no doubt that Lilla was dead; but when the lamp-light fell on her eyes, they seemed to look at Mimi with intent--with meaning. In this state of dark isolation a new resolution came to her, and grew and grew until it became a fixed definite purpose. She would face Caswall and call him to account for his murder of Lilla--that was what she called it to herself. She would also take steps--she knew not what or how--to avenge the part taken by Lady Arabella.

In this frame of mind she lit all the lamps in the room, got water and linen from her room, and set about the decent ordering of Lilla's body. This took some time; but when it was finished, she put on her hat and cloak, put out the lights, and set out quietly for Castra Regis.

As Mimi drew near the Castle, she saw no lights except those in and around the tower room. The lights showed her that Mr. Caswall was there, so she entered by the hall door, which as usual was open, and felt her way in the darkness up the staircase to the lobby of the room. The door was ajar, and the light from within showed brilliantly through the opening. She saw Edgar Caswall walking restlessly to and fro in the room, with his hands clasped behind his back. She opened the door without knocking, and walked right into the room. As she entered, he ceased walking, and stared at her in surprise. She made no remark, no comment, but continued the fixed look which he had seen on her entrance.

For a time silence reigned, and the two stood looking fixedly at each other. Mimi was the first to speak.

"You murderer! Lilla is dead!"

"Dead! Good God! When did she die?"

"She died this afternoon, just after you left her."

"Are you sure?"

"Yes--and so are you--or you ought to be. You killed her!"

"I killed her! Be careful what you say!"

"As God sees us, it is true; and you know it. You came to Mercy Farm on purpose to break her--if you could. And the accomplice of your guilt, Lady Arabella March, came for the same purpose."

"Be careful, woman," he said hotly. "Do not use such names in that way, or you shall suffer for it."

"I am suffering for it--have suffered for it--shall suffer for it. Not for speaking the truth as I have done, but because you two, with devilish malignity, did my darling to death. It is you and your accomplice who have to dread punishment, not I."

"Take care!" he said again.

"Oh, I am not afraid of you or your accomplice," she answered spiritedly. "I am content to stand by every word I have said, every act I have done. Moreover, I believe in God's justice. I fear not the grinding of His mills; if necessary I shall set the wheels in motion myself. But you don't care for God, or believe in Him. Your god is your great kite, which cows the birds of a whole district. But be sure that His hand, when it rises, always falls at the appointed time. It may be that your name is being called even at this very moment at the Great Assize. Repent while there is still time. Happy you, if you may be allowed to enter those mighty halls in the company of the pure-souled angel whose voice has only to whisper one word of justice, and you disappear for ever into everlasting torment."

The sudden death of Lilla caused consternation among Mimi's friends and well-wishers. Such a tragedy was totally unexpected, as Adam and Sir Nathaniel had been expecting the White Worm's vengeance to fall upon themselves.

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.

She followed on steadily through the gloom of the trees, depending on the glint of the white dress to keep her right. The wood began to thicken, and presently, when the road widened and the trees grew farther back, she lost sight of any indication of her whereabouts. Under the present conditions it was impossible for her to do any more, so, after waiting for a while, still hidden in the shadow to see if she could catch another glimpse of the white frock, she determined to go on slowly towards Castra Regis, and trust to the chapter of accidents to pick up the trail again. She went on slowly, taking advantage of every obstacle and shadow to keep herself concealed.

At last she entered on the grounds of the Castle, at a spot from which the windows of the turret were dimly visible, without having seen again any sign of Lady Arabella.

Meanwhile, during most of the time that Mimi Salton had been moving warily along in the gloom, she was in reality being followed by Lady Arabella, who had caught sight of her leaving the house and had never again lost touch with her. It was a case of the hunter being hunted. For a time Mimi's many turnings, with the natural obstacles that were perpetually intervening, caused Lady Arabella some trouble; but when she was close to Castra Regis, there was no more possibility of concealment, and the strange double following went swiftly on.

When she saw Mimi close to the hall door of Castra Regis and ascending the steps, she followed. When Mimi entered the dark hall and felt her way up the staircase, still, as she believed, following Lady Arabella, the latter kept on her way. When they reached the lobby of the turret-rooms, Mimi believed that the object of her search was ahead of her.

Edgar Caswall sat in the gloom of the great room, occasionally stirred to curiosity when the drifting clouds allowed a little light to fall from the storm-swept sky. But nothing really interested him now. Since he had heard of Lilla's death, the gloom of his remorse, emphasised by Mimi's upbraiding, had made more hopeless his cruel, selfish, saturnine nature. He heard no sound, for his normal faculties seemed benumbed.

Mimi, when she came to the door, which stood ajar, gave a light tap. So light was it that it did not reach Caswall's ears. Then, taking her courage in both hands, she boldly pushed the door and entered. As she did so, her heart sank, for now she was face to face with a difficulty which had not, in her state of mental perturbation, occurred to her.