The old mansion stood silently at the end of Blackwood Lane, its windows dark against the cold, grey November sky above. Detective Sarah Chen stepped out of her car and pulled her coat tighter against the bitter wind howling through the trees. A uniformed officer met her at the iron gate, his face pale and troubled beneath the flickering light of a streetlamp. "The body is in the study," he said quietly, gesturing toward the heavy oak door that stood slightly ajar before them. She nodded once and walked up the gravel path, her boots crunching steadily while dead leaves swirled around her tired feet. Inside, the air smelled of old books, expensive whiskey, and something else entirely, something metallic and wrong that filled her nostrils. The victim was a wealthy man named Arthur Blackwood, found slumped over his mahogany desk with a knife lodged in his back. His right hand still gripped an ivory fountain pen, and beneath it lay a letter that appeared to be hastily written. Three dinner guests had been in the house that evening, and every single one of them had a reason to want revenge. Sarah studied the scene carefully, memorizing every detail, knowing that somewhere in this room the killer had left a crucial hidden clue.