A Riddle in Bronze

merchants requesting payment for goods and services rendered, all mixed up with letters and invoices for the Twickhams' clients. The first dozen pages alone spanned the past week, and lines from several jumped out at me as I leafed through.
      Qr cwt Portland cement
      10 lb copper
      10 lb lead
      2 lb tin
      Cleansing and inspection, five pounds ten shillings.
      Half cwt charcoal
With enough to be going on with for the time being, I sat at the desk and began sorting a large pile of paperwork. Engrossed in my task, I scarcely noticed the passage of time until I reached the final page. Then, with the paperwork ready, I opened the most recent ledger in order to transfer the figures. I was met by neat columns of figures, and I nodded in approval as I saw the careful penmanship. Turning the pages, I discovered that the previous bookkeeper — whoever he or she might have been — had been fastidious and accurate.
The figures continued in this fashion until well into the ledger, but then something strange happened. As I turned the pages, I saw the neatness marred by frequent crossings-out and corrections. The lettering was no longer even and well-ordered, but instead became ragged and spiky, as though the author had suffered cramps in their fingers. Turning more pages, I saw gaps in the numbers, with random markings and symbols I did not recognise.
Then came two pages with hundreds of symbols scrawled one atop the next, forming an indecipherable jumble. And finally, as I turned to the final page, an oath escaped my lips. For there, scrawled across the page in a savage, barely-controlled hand, were the following words:
      KILL THEM!
            KILL THEM ALL!
– — Ω — –
I felt a cold sensation creeping over me as I stared at the ragged lettering scrawled on the page, and then I could stand it no more. Closing the ledger with a snap, I pushed it away from me in horror. What tortured soul had poured such vitriol onto the pages? What kind of slow, creeping madness had overtaken them?
For it was obvious from the dates in the ledger that this had not been a sudden transformation, triggered perhaps by an evening of strong liquor or drug-taking. No, this was a slow infusion of horror which had overtaken the bookkeeper day by day, week by week.
I felt a shiver up my spine, and I glanced around the small office. It felt like a malevolent presence was watching me.
Knock knock!
I started, then realised this had not been the taunting of some other-worldly spirit. No, it was merely someone at my door. "Enter," I called.
Elsie, the Twickhams' maid, came in carrying a silver platter. "A letter for you, sir," she said quietly. "Came by messenger, it did."
This was a surprise indeed, for nobody outside the household knew of my current address. "Are you sure it's not for the professor?"
"I can read, sir," said the girl, with a hint of rebuke in her voice.
"I'm sorry, I didn't mean to question you." She held out the platter without comment, and I took the letter. "Thank you, Elsie."
"Begging your pardon, but Mrs Fairacre will serve luncheon at noon."
"Excellent. Please tell her I am most grateful." I spoke absentmindedly, for I was inspecting the envelope, which was indeed addressed to me. Then, as the maid turned to leave, a sudden thought occurred to me. "Elsie, what do you know of my predecessor?"
She looked confused. "I'm sorry, sir?"
"The person who kept the accounts before me," I said, gesturing around the small office. "The person who worked in here. Did you know of them?"
She looked down at the floor. "I'm sure I can't say, Mr Jones. It's not my place to speak out."
"Very well. My thanks once more."
The door closed behind her, and I turned the envelope over and broke the seal. Inside was a single sheet of paper.
Attend the Crown and Feather after seven p.m., and you will learn something to your advantage.
At the bottom was a drawing of two triangles, entwined, but apart from this curious symbol the note bore no signature, nor any other clue as to the sender's identity. I raised the page to my nose, but there was no discernible scent, and I was just inspecting the envelope once more when I heard a commotion downstairs. I opened the door and heard a clatter of footsteps in the hallway, and then Roberta's distraught voice.
"Elsie, help him to the sitting room!" she cried. "Quick now, and fetch brandy!"
I dashed from my office and bounded downstairs, leaping the steps two at a time. At the bottom, I saw Roberta and the maid supporting Professor Twickham, who looked as near-death as I've ever seen a man. His face was pallid and his head lolled to one side, his movements feeble and helpless. But then, as he was half-carried through the doorway to the lounge, his eyes met mine, and I drew a shuddering breath. The orbs were entirely black, as though fashioned from the night sky, and at the sight of such horror I let out an involuntary cry.
"Don't just stand there!" shouted Roberta, catching sight of me. "Come and help him!"
– — Ω — –
The three of us guided the professor to an armchair, knocking over a side table in our hurry. Knick-knacks and mementos scattered on the rug, and Elsie automatically crouched to pick them up.
"Leave that!" shouted Roberta. "Brandy."
"Yes, ma'am," said Elsie, and she fled the room.
Meanwhile Roberta had knelt before her father, and was feeling his wrist. He'd slumped in the chair, those dark eyes now hidden behind closed eyelids, and with growing horror I feared he might have breathed his last. But when Roberta slapped his cheek, none too gently, he groaned and struggled to sit up. "Father, can you hear me?"
Elsie returned with a glass brimming with brandy, and Roberta snatched it