"You did n't see it?"
We had paused at the head of the stairs, two of us nonplussed and very curious. I shook my head.
"When you left the room," said I, "I was too occupied otherwise to be heeding the curtained alcove. I wondered, though, what sudden impulse moved you—why you should have gone into the alcove at all."
"I knew that you could not leave the room right then," she explained, the color coming quickly back to her cheeks; "I remembered our pact, and I thought I saw an opportunity of being really of assistance. It is not to be wondered at that nobody else saw what I did. It all happened so swiftly. By the merest chance I glanced toward the alcove, and at that very instant the curtains parted sufficiently for me to see a face." Again she shuddered.
"Mr. Swift, it was the most hideous face I ever looked upon. Had I been alone in the library doubtless it would have terrified me even then. But instantly it disappeared, and without a thought of being afraid, I hastened to investigate.
"As I got to the conservatory I saw the door at the farther end just closing. It didn't slam—there was n't a sound—but simply closed quickly before my eyes. Never for a moment did it occur to me that I ought to be cautious; that closing door only made me run the faster to learn who or what had closed it.
"Well, when I opened it, and the next door across the little passage, I saw the same thing repeated in the bedroom beyond—a door closing, apparently from its own volition. The same thing happened with the door opening into the rear hall.
"It was maddening to be just so far behind and unable to gain the fraction of a second which would enable me to find out who was fleeing from me in such haste—maddening to be rewarded with no more than a procession of closing doors.
"The chase continued on up the rear stairs, to the landing between the bath room and the small room at the back; there for the first time I felt a misgiving, and I hesitated. I was out of breath, my heart was pounding until my ears roared; everything else was so deathly still.
"A glance told me that the rear room was empty of any living presence. Cautiously I pushed open the bath room door; but it was too dark to see inside."