If it had an occupant he would, in all probability, have a light, therefore he switched off his torch and tried to discover any ray of light shining through a crack.
Carefully he went around the whole door, until he drew away the mat before it, when, sure enough, a light showed from within!
With bated breath he listened. He could, however, distinguish no sound, even though he placed his ear to the floor. Then, raising himself, much gratified at his discovery, but nevertheless increasingly puzzled, he recollected that the occupant, whoever he might be, would no doubt have heard his footsteps and was now remaining quiet, little dreaming that his light had betrayed his presence.
Suddenly, as he stood there straining his ears, he heard the sound of low ticking—the ticking of a clock. Again he bent his ear to the bottom of the door, and then at once established the fact that the clock was inside that locked room.
He heard Marigold coming up from below, and at once slipped down again, meeting her in the hall. When within the sitting-room, he said to her in a low, tense voice:
"There's somebody in that room! There's a light there!"
"Your first surmise is correct then, Gerald!" she exclaimed. "Who can it possibly be?"
"Ah! that we have to discover!" he said. "Let's be patient. I wonder, however, who can be living up there in secret. At any rate, he has both light and the time of day. In this weather he only wants food and water."
"But it's extraordinary that somebody should live here without my aunt's knowledge."
"It is. But there are dozens of people hidden away in London—people believed by their friends to be dead, or abroad," he said. "In a great city like ours it is quite easy to hide, providing that one is concealed by a trusty friend. I wonder," he added, "how many people whose obituary notices have appeared in the papers are living in secret in upstairs rooms or down in cellars, dragging out their lives in self-imprisonment, yet buoyed by the hope that one day they may, when changed in appearance by years, reappear among their fellow-men and laugh up their sleeves because nobody recognises them."