The fraternal designation by which the bizarre, sable-dad female had addressed me—combined with the close, if not uncanny, resemblance between her features and my own—served to confirm the hypothesis I had so recently set forth to Crockett: viz. that the killer we were seeking was none other than a long-unknown sibling, sired by my own reprobate father. Having set out to demonstrate the superiority of pure, deductive reasoning over mere brute strength, I would—under ordinary circumstances—have felt a keen sense of vindication at this confirmation of my theories.

Owing to a variety of factors, however—the dreadful ordeals of the day, the unnerving atmosphere of the subterranean vault in which I now stood, the sheer indescribable strangeness of finding myself face to face with my sinister female double—my reaction was substantially different. Emitting a gasp of dismay, I staggered backwards several steps while loosening my grip upon the blazing torch, which fell from my hand, struck the uneven stone floor, and—rolling beside a large oil painting of a moonlit landscape that leaned against one wall—immediately ignited the wooden frame.

With a sharp intake of breath, my distaff counterpart snatched up the water jug and—striding swiftly to the enkindled oil painting—doused the incipient fire. Then, turning to me with a look of solemn reproach, she declared:

“One conflagration has already ravaged this house. Surely that is sufficient.”

“A conflagration,” I replied in a tremulous voice, “ignited by yourself.”

“Yes,” she replied, her pallid lips forming themselves into a smile of grim satisfaction. “It was I who brought down this proud and stately dwelling!”

“But why?” I asked, although I had already surmised the answer.

As if endowed with a preternatural faculty that permitted her to read my very thoughts, she replied: “But have you not already guessed?”

“Yes,” I acknowledged after a momentary pause. “Vengeance.”

“Even so,” said she. “Vengeance on those who brought ruin upon him.”

For a moment, I merely stared in awe-struck silence at the wan—slender—and seemingly delicate creature who had wrought such mayhem on so many. Making allowances for the differences in our respective genders—and the presence, in my own case, of the neatly trimmed moustache that adorned my upper lip—our two visages were remarkably alike. She was a singularly handsome young woman, endowed with a smooth and lofty forehead—luxuriant tresses of jetty hair—a nose of graceful, Grecian mold—and a pale, voluptuous mouth behind whose slightly parted lips I could clearly perceive her small, narrow, and excessively white teeth.

Only one intensely unnerving feature detracted from the placid loveliness of her appearance—the strange, unnatural luminosity of her enormous, dark eyes, which glinted with the hysterical brilliancy of barely suppressed madness!

“So it is true,” I observed at length. “You are indeed his child.”

“I am,” she smilingly replied, taking another step in my direction. “And your own dear half-sister.”