He caught hold of Cotter's limp arm and propelled him up the stairs. The atmosphere was clean and sweet now, though traces of the perfume lingered. Cotter, hanging limply from Wilfrid's arm, pointed to a door. Then he turned and fled, holding on by the balustrade. It was no time to hesitate, so Wilfrid tapped at the door. His heart was in his mouth and he waited with sickening impatience for a reply. Suppose the mischief had been done! Suppose he should be too late! He had with difficulty saved himself. Then he gave a gasp of relief as he heard the voice of Beatrice asking who was there.
"It is I, Mercer," he said. "There is no time to lose. Will you unlock the door?"
CHAPTER IX
BEHIND LOCKED DOORS
"I cannot," Beatrice replied. Her voice was low, but to Wilfrid's relief quite steady. "The door is locked on the outside. I am so thankful you have come."
Wilfrid turned the key. With a great thrill of delight he saw that Beatrice was little the worse for what she had gone through. He indulged in no idle talk, but reached out his hand in search of one of the electric switches. Beatrice grasped Wilfrid's meaning. She stretched out her hand and immediately the corridor was flooded with light.
"I cannot understand it," she murmured. "Dr. Mercer, what does it mean?"
"Perhaps you had better tell me your experience first," Wilfrid suggested. "If I can throw any light afterwards on this hideous mystery I shall be glad."
"I'll tell you as collectedly as I can," Beatrice replied. "I had almost forgotten the alarm I had in the conservatory this afternoon when I came up to bed. I sat for a while dreaming over the fire——"
Beatrice stopped and a little colour crept into her face. She wondered what Wilfrid would say if he only knew what she had been thinking about. He nodded encouragingly.