Mildred leapt to her feet, while the blood rushed into her cheeks and her heart began to beat furiously. She was not in the least frightened. What she felt at that moment was something almost like triumph. Lady Sarah had been committed to her charge, and she was now in danger. Here was a chance of redeeming her misdoings of the day before; an opportunity of saving her from threatened danger! Mildred slipped on dressing-gown and slippers and laid her hand on the knob of the door. Before she had time to open it, however, a faint rustling from without attracted her attention; she listened, and could discern the almost imperceptible sound of footsteps coming along the corridor from Lady Sarah's room, and towards her own. Outside her door they paused, and it seemed as if the beating of her heart must surely betray her presence. But no, they moved on again, the swish of the trailing skirts growing fainter and fainter, until it died away in the distance. Mildred opened the door and peered cautiously into the passage. All was dark and silent, but on the wall above the staircase a faint light flickered, now here, now there, as if reflected from a candle carried in the hand of someone descending to the hall beneath. Mildred darted in pursuit along the passage, her thick padded slippers aiding her characteristic lightness of movement, so that she reached a point where she could get the desired view without making a sound that could have been heard by the most watchful ears. It was as she thought. Someone was creeping downstairs, candle in hand, and feeble as the flame was, it was sufficient to light up the sleek head, the slight, sinuous figure of Lady Sarah's maid. Mildred pressed her lips together with a look of comprehension, and immediately faced round to retrace her steps with even more speed than before. This time she did not stop short at her own room, but turned into the further passage from which Lady Sarah's room was entered. The key was in the lock, for Cecile had carefully fastened the old lady in the room before she herself had taken her departure, but Mildred gave a fine smile of contempt as she drew it out, and slipped it into the pocket of her dressing-gown. Another moment and she was within the room, standing by Lady Sarah's bed and gazing upon the face which lay on the pillow with startled eyes.